Adding upstream version 0.70.1+ds1.upstream/0.70.1+ds1 upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-04 12:47:55 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-04 12:47:55 +0000
commit: 2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4 (patch)
tree: 033cc839730fda84ff08db877037977be94e5e3a /vendor/once_cell
parent: Initial commit. (diff)
download: cargo-2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4.tar.xz
cargo-2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4.zip
28 files changed, 4553 insertions, 0 deletions
diff --git a/vendor/once_cell/.cargo-checksum.json b/vendor/once_cell/.cargo-checksum.json
new file mode 100644
index 0000000..c8f9b26
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+++ b/vendor/once_cell/.cargo-checksum.json
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+{"files":{},"package":"dd8b5dd2ae5ed71462c540258bedcb51965123ad7e7ccf4b9a8cafaa4a63576d"}
+\ No newline at end of file
diff --git a/vendor/once_cell/CHANGELOG.md b/vendor/once_cell/CHANGELOG.md
new file mode 100644
index 0000000..0cb846a
--- /dev/null
+++ b/vendor/once_cell/CHANGELOG.md
@@ -0,0 +1,225 @@
+# Changelog
+
+## Unreleased
+
+- 
+
+## 1.18.0
+
+- `MSRV` is updated to 1.60.0 to take advantage of `dep:` syntax for cargo features,
+  removing "implementation details" from publicly visible surface.
+
+## 1.17.2
+
+- Avoid unnecessary synchronization in `Lazy::{force,deref}_mut()`, [#231](https://github.com/matklad/once_cell/pull/231).
+
+## 1.17.1
+
+- Make `OnceRef` implementation compliant with [strict provenance](https://github.com/rust-lang/rust/issues/95228).
+
+## 1.17.0
+
+- Add `race::OnceRef` for storing a `&'a T`.
+
+## 1.16.0
+
+- Add `no_std` implementation based on `critical-section`,
+  [#195](https://github.com/matklad/once_cell/pull/195).
+- Deprecate `atomic-polyfill` feature (use the new `critical-section` instead)
+
+## 1.15.0
+
+- Increase minimal supported Rust version to 1.56.0.
+- Implement `UnwindSafe` even if the `std` feature is disabled.
+
+## 1.14.0
+
+- Add extension to `unsync` and `sync` `Lazy` mut API:
+  - `force_mut`
+  - `get_mut`
+
+
+## 1.13.1
+
+- Make implementation compliant with [strict provenance](https://github.com/rust-lang/rust/issues/95228).
+- Upgrade `atomic-polyfill` to `1.0`
+
+## 1.13.0
+
+- Add `Lazy::get`, similar to `OnceCell::get`.
+
+## 1.12.1
+
+- Remove incorrect `debug_assert`.
+
+## 1.12.0
+
+- Add `OnceCell::wait`, a blocking variant of `get`.
+
+## 1.11.0
+
+- Add `OnceCell::with_value` to create initialized `OnceCell` in `const` context.
+- Improve `Clone` implementation for `OnceCell`.
+- Rewrite `parking_lot` version on top of `parking_lot_core`, for even smaller cells!
+
+## 1.10.0
+
+- upgrade `parking_lot` to `0.12.0` (note that this bumps MSRV with `parking_lot` feature enabled to `1.49.0`).
+
+## 1.9.0
+
+- Added an `atomic-polyfill` optional dependency to compile `race` on platforms without atomics
+
+## 1.8.0
+
+- Add `try_insert` API -- a version of `set` that returns a reference.
+
+## 1.7.2
+
+- Improve code size when using parking_lot feature.
+
+## 1.7.1
+
+- Fix `race::OnceBox<T>` to also impl `Default` even if `T` doesn't impl `Default`.
+
+## 1.7.0
+
+- Hide the `race` module behind (default) `race` feature.
+  Turns out that adding `race` by default was a breaking change on some platforms without atomics.
+  In this release, we make the module opt-out.
+  Technically, this is a breaking change for those who use `race` with `no_default_features`.
+  Given that the `race` module itself only several days old, the breakage is deemed acceptable.
+
+## 1.6.0
+
+- Add `Lazy::into_value`
+- Stabilize `once_cell::race` module for "first one wins" no_std-compatible initialization flavor.
+- Migrate from deprecated `compare_and_swap` to `compare_exchange`.
+
+## 1.5.2
+
+- `OnceBox` API uses `Box<T>`.
+  This a breaking change to unstable API.
+
+## 1.5.1
+
+- MSRV is increased to `1.36.0`.
+- document `once_cell::race` module.
+- introduce `alloc` feature for `OnceBox`.
+- fix `OnceBox::set`.
+
+## 1.5.0
+
+- add new `once_cell::race` module for "first one wins" no_std-compatible initialization flavor.
+  The API is provisional, subject to change and is gated by the `unstable` cargo feature.
+
+## 1.4.1
+
+- upgrade `parking_lot` to `0.11.0`
+- make `sync::OnceCell<T>` pass https://doc.rust-lang.org/nomicon/dropck.html#an-escape-hatch[dropck] with `parking_lot` feature enabled.
+  This fixes a (minor) semver-incompatible changed introduced in `1.4.0`
+
+## 1.4.0
+
+- upgrade `parking_lot` to `0.10` (note that this bumps MSRV with `parking_lot` feature enabled to `1.36.0`).
+- add `OnceCell::take`.
+- upgrade crossbeam utils (private dependency) to `0.7`.
+
+## 1.3.1
+
+- remove unnecessary `F: fmt::Debug` bound from `impl fmt::Debug for Lazy<T, F>`.
+
+## 1.3.0
+
+- `Lazy<T>` now implements `DerefMut`.
+- update implementation according to the latest changes in `std`.
+
+## 1.2.0
+
+- add `sync::OnceCell::get_unchecked`.
+
+## 1.1.0
+
+- implement `Default` for `Lazy`: it creates an empty `Lazy<T>` which is initialized with `T::default` on first access.
+- add `OnceCell::get_mut`.
+
+## 1.0.2
+
+- actually add `#![no_std]` attribute if std feature is not enabled.
+
+## 1.0.1
+
+- fix unsoundness in `Lazy<T>` if the initializing function panics. Thanks [@xfix](https://github.com/xfix)!
+- implement `RefUnwindSafe` for `Lazy`.
+- share more code between `std` and `parking_lot` implementations.
+- add F.A.Q section to the docs.
+
+## 1.0.0
+
+- remove `parking_lot` from the list of default features.
+- add `std` default feature. Without `std`, only `unsync` module is supported.
+- implement `Eq` for `OnceCell`.
+- fix wrong `Sync` bound on `sync::Lazy`.
+- run the whole test suite with miri.
+
+## 0.2.7
+
+- New implementation of `sync::OnceCell` if `parking_lot` feature is disabled.
+  It now employs a hand-rolled variant of `std::sync::Once`.
+- `sync::OnceCell::get_or_try_init` works without `parking_lot` as well!
+- document the effects of `parking_lot` feature: same performance but smaller types.
+
+## 0.2.6
+
+- Updated `Lazy`'s `Deref` impl to requires only `FnOnce` instead of `Fn`
+
+## 0.2.5
+
+- `Lazy` requires only `FnOnce` instead of `Fn`
+
+## 0.2.4
+
+- nicer `fmt::Debug` implementation
+
+## 0.2.3
+
+- update `parking_lot` to `0.9.0`
+- fix stacked borrows violation in `unsync::OnceCell::get`
+- implement `Clone` for `sync::OnceCell<T> where T: Clone`
+
+## 0.2.2
+
+- add `OnceCell::into_inner` which consumes a cell and returns an option
+
+## 0.2.1
+
+- implement `sync::OnceCell::get_or_try_init` if `parking_lot` feature is enabled
+- switch internal `unsafe` implementation of `sync::OnceCell` from `Once` to `Mutex`
+- `sync::OnceCell::get_or_init` is twice as fast if cell is already initialized
+- implement `std::panic::RefUnwindSafe` and `std::panic::UnwindSafe` for `OnceCell`
+- better document behavior around panics
+
+## 0.2.0
+
+- MSRV is now 1.31.1
+- `Lazy::new` and `OnceCell::new` are now const-fns
+- `unsync_lazy` and `sync_lazy` macros are removed
+
+## 0.1.8
+
+- update crossbeam-utils to 0.6
+- enable bors-ng
+
+## 0.1.7
+
+- cells implement `PartialEq` and `From`
+- MSRV is down to 1.24.1
+- update `parking_lot` to `0.7.1`
+
+## 0.1.6
+
+- `unsync::OnceCell<T>` is `Clone` if `T` is `Clone`.
+
+## 0.1.5
+
+- No changelog until this point :(
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diff --git a/vendor/once_cell/Cargo.toml b/vendor/once_cell/Cargo.toml
new file mode 100644
index 0000000..b3a6ba6
--- /dev/null
+++ b/vendor/once_cell/Cargo.toml
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+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+rust-version = "1.60"
+name = "once_cell"
+version = "1.18.0"
+authors = ["Aleksey Kladov <aleksey.kladov@gmail.com>"]
+exclude = [
+    "*.png",
+    "*.svg",
+    "/Cargo.lock.msrv",
+    "rustfmt.toml",
+]
+description = "Single assignment cells and lazy values."
+documentation = "https://docs.rs/once_cell"
+readme = "README.md"
+keywords = [
+    "lazy",
+    "static",
+]
+categories = [
+    "rust-patterns",
+    "memory-management",
+]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/matklad/once_cell"
+
+[package.metadata.docs.rs]
+all-features = true
+
+[[example]]
+name = "bench"
+required-features = ["std"]
+
+[[example]]
+name = "bench_acquire"
+required-features = ["std"]
+
+[[example]]
+name = "lazy_static"
+required-features = ["std"]
+
+[[example]]
+name = "reentrant_init_deadlocks"
+required-features = ["std"]
+
+[[example]]
+name = "regex"
+required-features = ["std"]
+
+[[example]]
+name = "test_synchronization"
+required-features = ["std"]
+
+[dependencies.atomic-polyfill]
+version = "1"
+optional = true
+
+[dependencies.critical-section]
+version = "1"
+optional = true
+
+[dependencies.parking_lot_core]
+version = "0.9.3"
+optional = true
+default_features = false
+
+[dev-dependencies.critical-section]
+version = "1.1.1"
+features = ["std"]
+
+[dev-dependencies.regex]
+version = "1.2.0"
+
+[features]
+alloc = ["race"]
+atomic-polyfill = ["critical-section"]
+critical-section = [
+    "dep:critical-section",
+    "dep:atomic-polyfill",
+]
+default = ["std"]
+parking_lot = ["dep:parking_lot_core"]
+race = []
+std = ["alloc"]
+unstable = []
diff --git a/vendor/once_cell/LICENSE-APACHE b/vendor/once_cell/LICENSE-APACHE
new file mode 100644
index 0000000..16fe87b
--- /dev/null
+++ b/vendor/once_cell/LICENSE-APACHE
@@ -0,0 +1,201 @@
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diff --git a/vendor/once_cell/LICENSE-MIT b/vendor/once_cell/LICENSE-MIT
new file mode 100644
index 0000000..31aa793
--- /dev/null
+++ b/vendor/once_cell/LICENSE-MIT
@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/vendor/once_cell/README.md b/vendor/once_cell/README.md
new file mode 100644
index 0000000..737f2de
--- /dev/null
+++ b/vendor/once_cell/README.md
@@ -0,0 +1,58 @@
+<p align="center"><img src="design/logo.png" alt="once_cell"></p>
+
+
+[![Build Status](https://github.com/matklad/once_cell/actions/workflows/ci.yaml/badge.svg)](https://github.com/matklad/once_cell/actions)
+[![Crates.io](https://img.shields.io/crates/v/once_cell.svg)](https://crates.io/crates/once_cell)
+[![API reference](https://docs.rs/once_cell/badge.svg)](https://docs.rs/once_cell/)
+
+# Overview
+
+`once_cell` provides two new cell-like types, `unsync::OnceCell` and `sync::OnceCell`. `OnceCell`
+might store arbitrary non-`Copy` types, can be assigned to at most once and provide direct access
+to the stored contents. In a nutshell, API looks *roughly* like this:
+
+```rust
+impl OnceCell<T> {
+    fn new() -> OnceCell<T> { ... }
+    fn set(&self, value: T) -> Result<(), T> { ... }
+    fn get(&self) -> Option<&T> { ... }
+}
+```
+
+Note that, like with `RefCell` and `Mutex`, the `set` method requires only a shared reference.
+Because of the single assignment restriction `get` can return an `&T` instead of `Ref<T>`
+or `MutexGuard<T>`.
+
+`once_cell` also has a `Lazy<T>` type, build on top of `OnceCell` which provides the same API as
+the `lazy_static!` macro, but without using any macros:
+
+```rust
+use std::{sync::Mutex, collections::HashMap};
+use once_cell::sync::Lazy;
+
+static GLOBAL_DATA: Lazy<Mutex<HashMap<i32, String>>> = Lazy::new(|| {
+    let mut m = HashMap::new();
+    m.insert(13, "Spica".to_string());
+    m.insert(74, "Hoyten".to_string());
+    Mutex::new(m)
+});
+
+fn main() {
+    println!("{:?}", GLOBAL_DATA.lock().unwrap());
+}
+```
+
+More patterns and use-cases are in the [docs](https://docs.rs/once_cell/)!
+
+# Related crates
+
+* [double-checked-cell](https://github.com/niklasf/double-checked-cell)
+* [lazy-init](https://crates.io/crates/lazy-init)
+* [lazycell](https://crates.io/crates/lazycell)
+* [mitochondria](https://crates.io/crates/mitochondria)
+* [lazy_static](https://crates.io/crates/lazy_static)
+* [async_once_cell](https://crates.io/crates/async_once_cell)
+* [generic_once_cell](https://crates.io/crates/generic_once_cell) (bring your own mutex)
+
+The API of `once_cell` is being proposed for inclusion in
+[`std`](https://github.com/rust-lang/rfcs/pull/2788).
diff --git a/vendor/once_cell/bors.toml b/vendor/once_cell/bors.toml
new file mode 100644
index 0000000..b92b99a
--- /dev/null
+++ b/vendor/once_cell/bors.toml
@@ -0,0 +1,2 @@
+status = [ "Rust" ]
+delete_merged_branches = true
diff --git a/vendor/once_cell/debian/patches/relax-test.diff b/vendor/once_cell/debian/patches/relax-test.diff
new file mode 100644
index 0000000..bc58a8c
--- /dev/null
+++ b/vendor/once_cell/debian/patches/relax-test.diff
@@ -0,0 +1,12 @@
+--- a/tests/it/sync_once_cell.rs
++++ b/tests/it/sync_once_cell.rs
+@@ -395,3 +395,3 @@
+ 
+-#[test]
++/*#[test]
+ #[cfg_attr(miri, ignore)] // miri doesn't support processes
+@@ -422,3 +422,3 @@
+     }
+-}
++}*/
+ 
diff --git a/vendor/once_cell/debian/patches/series b/vendor/once_cell/debian/patches/series
new file mode 100644
index 0000000..68285d3
--- /dev/null
+++ b/vendor/once_cell/debian/patches/series
@@ -0,0 +1 @@
+relax-test.diff
diff --git a/vendor/once_cell/examples/bench.rs b/vendor/once_cell/examples/bench.rs
new file mode 100644
index 0000000..e680125
--- /dev/null
+++ b/vendor/once_cell/examples/bench.rs
@@ -0,0 +1,28 @@
+use std::mem::size_of;
+
+use once_cell::sync::OnceCell;
+
+const N_THREADS: usize = 32;
+const N_ROUNDS: usize = 100_000_000;
+
+static CELL: OnceCell<usize> = OnceCell::new();
+
+fn main() {
+    let start = std::time::Instant::now();
+    let threads =
+        (0..N_THREADS).map(|i| std::thread::spawn(move || thread_main(i))).collect::<Vec<_>>();
+    for thread in threads {
+        thread.join().unwrap();
+    }
+    println!("{:?}", start.elapsed());
+    println!("size_of::<OnceCell<()>>()   = {:?}", size_of::<OnceCell<()>>());
+    println!("size_of::<OnceCell<bool>>() = {:?}", size_of::<OnceCell<bool>>());
+    println!("size_of::<OnceCell<u32>>()  = {:?}", size_of::<OnceCell<u32>>());
+}
+
+fn thread_main(i: usize) {
+    for _ in 0..N_ROUNDS {
+        let &value = CELL.get_or_init(|| i);
+        assert!(value < N_THREADS)
+    }
+}
diff --git a/vendor/once_cell/examples/bench_acquire.rs b/vendor/once_cell/examples/bench_acquire.rs
new file mode 100644
index 0000000..1518047
--- /dev/null
+++ b/vendor/once_cell/examples/bench_acquire.rs
@@ -0,0 +1,39 @@
+//! Benchmark the overhead that the synchronization of `OnceCell::get` causes.
+//! We do some other operations that write to memory to get an imprecise but somewhat realistic
+//! measurement.
+
+use once_cell::sync::OnceCell;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+const N_THREADS: usize = 16;
+const N_ROUNDS: usize = 1_000_000;
+
+static CELL: OnceCell<usize> = OnceCell::new();
+static OTHER: AtomicUsize = AtomicUsize::new(0);
+
+fn main() {
+    let start = std::time::Instant::now();
+    let threads =
+        (0..N_THREADS).map(|i| std::thread::spawn(move || thread_main(i))).collect::<Vec<_>>();
+    for thread in threads {
+        thread.join().unwrap();
+    }
+    println!("{:?}", start.elapsed());
+    println!("{:?}", OTHER.load(Ordering::Relaxed));
+}
+
+#[inline(never)]
+fn thread_main(i: usize) {
+    // The operations we do here don't really matter, as long as we do multiple writes, and
+    // everything is messy enough to prevent the compiler from optimizing the loop away.
+    let mut data = [i; 128];
+    let mut accum = 0usize;
+    for _ in 0..N_ROUNDS {
+        let _value = CELL.get_or_init(|| i + 1);
+        let k = OTHER.fetch_add(data[accum & 0x7F] as usize, Ordering::Relaxed);
+        for j in data.iter_mut() {
+            *j = (*j).wrapping_add(accum);
+            accum = accum.wrapping_add(k);
+        }
+    }
+}
diff --git a/vendor/once_cell/examples/lazy_static.rs b/vendor/once_cell/examples/lazy_static.rs
new file mode 100644
index 0000000..3cdb19f
--- /dev/null
+++ b/vendor/once_cell/examples/lazy_static.rs
@@ -0,0 +1,36 @@
+extern crate once_cell;
+
+use once_cell::sync::{Lazy, OnceCell};
+use std::collections::HashMap;
+
+static HASHMAP: Lazy<HashMap<u32, &'static str>> = Lazy::new(|| {
+    let mut m = HashMap::new();
+    m.insert(0, "foo");
+    m.insert(1, "bar");
+    m.insert(2, "baz");
+    m
+});
+
+// Same, but completely without macros
+fn hashmap() -> &'static HashMap<u32, &'static str> {
+    static INSTANCE: OnceCell<HashMap<u32, &'static str>> = OnceCell::new();
+    INSTANCE.get_or_init(|| {
+        let mut m = HashMap::new();
+        m.insert(0, "foo");
+        m.insert(1, "bar");
+        m.insert(2, "baz");
+        m
+    })
+}
+
+fn main() {
+    // First access to `HASHMAP` initializes it
+    println!("The entry for `0` is \"{}\".", HASHMAP.get(&0).unwrap());
+
+    // Any further access to `HASHMAP` just returns the computed value
+    println!("The entry for `1` is \"{}\".", HASHMAP.get(&1).unwrap());
+
+    // The same works for function-style:
+    assert_eq!(hashmap().get(&0), Some(&"foo"));
+    assert_eq!(hashmap().get(&1), Some(&"bar"));
+}
diff --git a/vendor/once_cell/examples/reentrant_init_deadlocks.rs b/vendor/once_cell/examples/reentrant_init_deadlocks.rs
new file mode 100644
index 0000000..af4b5b7
--- /dev/null
+++ b/vendor/once_cell/examples/reentrant_init_deadlocks.rs
@@ -0,0 +1,14 @@
+fn main() {
+    let cell = once_cell::sync::OnceCell::<u32>::new();
+    cell.get_or_init(|| {
+        cell.get_or_init(|| 1);
+        2
+    });
+}
+
+/// Dummy test to make it seem hang when compiled as `--test`
+/// See https://github.com/matklad/once_cell/issues/79
+#[test]
+fn dummy_test() {
+    std::thread::sleep(std::time::Duration::from_secs(4));
+}
diff --git a/vendor/once_cell/examples/regex.rs b/vendor/once_cell/examples/regex.rs
new file mode 100644
index 0000000..4c4c2ea
--- /dev/null
+++ b/vendor/once_cell/examples/regex.rs
@@ -0,0 +1,49 @@
+use std::{str::FromStr, time::Instant};
+
+use regex::Regex;
+
+macro_rules! regex {
+    ($re:literal $(,)?) => {{
+        static RE: once_cell::sync::OnceCell<regex::Regex> = once_cell::sync::OnceCell::new();
+        RE.get_or_init(|| regex::Regex::new($re).unwrap())
+    }};
+}
+
+fn slow() {
+    let s = r##"13.28.24.13 - - [10/Mar/2016:19:29:25 +0100] "GET /etc/lib/pChart2/examples/index.php?Action=View&Script=../../../../cnf/db.php HTTP/1.1" 404 151 "-" "HTTP_Request2/2.2.1 (http://pear.php.net/package/http_request2) PHP/5.3.16""##;
+
+    let mut total = 0;
+    for _ in 0..1000 {
+        let re = Regex::new(
+            r##"^(\S+) (\S+) (\S+) \[([^]]+)\] "([^"]*)" (\d+) (\d+) "([^"]*)" "([^"]*)"$"##,
+        )
+        .unwrap();
+        let size = usize::from_str(re.captures(s).unwrap().get(7).unwrap().as_str()).unwrap();
+        total += size;
+    }
+    println!("{}", total);
+}
+
+fn fast() {
+    let s = r##"13.28.24.13 - - [10/Mar/2016:19:29:25 +0100] "GET /etc/lib/pChart2/examples/index.php?Action=View&Script=../../../../cnf/db.php HTTP/1.1" 404 151 "-" "HTTP_Request2/2.2.1 (http://pear.php.net/package/http_request2) PHP/5.3.16""##;
+
+    let mut total = 0;
+    for _ in 0..1000 {
+        let re: &Regex = regex!(
+            r##"^(\S+) (\S+) (\S+) \[([^]]+)\] "([^"]*)" (\d+) (\d+) "([^"]*)" "([^"]*)"$"##,
+        );
+        let size = usize::from_str(re.captures(s).unwrap().get(7).unwrap().as_str()).unwrap();
+        total += size;
+    }
+    println!("{}", total);
+}
+
+fn main() {
+    let t = Instant::now();
+    slow();
+    println!("slow: {:?}", t.elapsed());
+
+    let t = Instant::now();
+    fast();
+    println!("fast: {:?}", t.elapsed());
+}
diff --git a/vendor/once_cell/examples/test_synchronization.rs b/vendor/once_cell/examples/test_synchronization.rs
new file mode 100644
index 0000000..0d54f98
--- /dev/null
+++ b/vendor/once_cell/examples/test_synchronization.rs
@@ -0,0 +1,38 @@
+//! Test if the OnceCell properly synchronizes.
+//! Needs to be run in release mode.
+//!
+//! We create a `Vec` with `N_ROUNDS` of `OnceCell`s. All threads will walk the `Vec`, and race to
+//! be the first one to initialize a cell.
+//! Every thread adds the results of the cells it sees to an accumulator, which is compared at the
+//! end.
+//! All threads should end up with the same result.
+
+use once_cell::sync::OnceCell;
+
+const N_THREADS: usize = 32;
+const N_ROUNDS: usize = 1_000_000;
+
+static CELLS: OnceCell<Vec<OnceCell<usize>>> = OnceCell::new();
+static RESULT: OnceCell<usize> = OnceCell::new();
+
+fn main() {
+    let start = std::time::Instant::now();
+    CELLS.get_or_init(|| vec![OnceCell::new(); N_ROUNDS]);
+    let threads =
+        (0..N_THREADS).map(|i| std::thread::spawn(move || thread_main(i))).collect::<Vec<_>>();
+    for thread in threads {
+        thread.join().unwrap();
+    }
+    println!("{:?}", start.elapsed());
+    println!("No races detected");
+}
+
+fn thread_main(i: usize) {
+    let cells = CELLS.get().unwrap();
+    let mut accum = 0;
+    for cell in cells.iter() {
+        let &value = cell.get_or_init(|| i);
+        accum += value;
+    }
+    assert_eq!(RESULT.get_or_init(|| accum), &accum);
+}
diff --git a/vendor/once_cell/src/imp_cs.rs b/vendor/once_cell/src/imp_cs.rs
new file mode 100644
index 0000000..04018f1
--- /dev/null
+++ b/vendor/once_cell/src/imp_cs.rs
@@ -0,0 +1,78 @@
+use core::panic::{RefUnwindSafe, UnwindSafe};
+
+use atomic_polyfill::{AtomicBool, Ordering};
+use critical_section::{CriticalSection, Mutex};
+
+use crate::unsync;
+
+pub(crate) struct OnceCell<T> {
+    initialized: AtomicBool,
+    // Use `unsync::OnceCell` internally since `Mutex` does not provide
+    // interior mutability and to be able to re-use `get_or_try_init`.
+    value: Mutex<unsync::OnceCell<T>>,
+}
+
+// Why do we need `T: Send`?
+// Thread A creates a `OnceCell` and shares it with
+// scoped thread B, which fills the cell, which is
+// then destroyed by A. That is, destructor observes
+// a sent value.
+unsafe impl<T: Sync + Send> Sync for OnceCell<T> {}
+unsafe impl<T: Send> Send for OnceCell<T> {}
+
+impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
+impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}
+
+impl<T> OnceCell<T> {
+    pub(crate) const fn new() -> OnceCell<T> {
+        OnceCell { initialized: AtomicBool::new(false), value: Mutex::new(unsync::OnceCell::new()) }
+    }
+
+    pub(crate) const fn with_value(value: T) -> OnceCell<T> {
+        OnceCell {
+            initialized: AtomicBool::new(true),
+            value: Mutex::new(unsync::OnceCell::with_value(value)),
+        }
+    }
+
+    #[inline]
+    pub(crate) fn is_initialized(&self) -> bool {
+        self.initialized.load(Ordering::Acquire)
+    }
+
+    #[cold]
+    pub(crate) fn initialize<F, E>(&self, f: F) -> Result<(), E>
+    where
+        F: FnOnce() -> Result<T, E>,
+    {
+        critical_section::with(|cs| {
+            let cell = self.value.borrow(cs);
+            cell.get_or_try_init(f).map(|_| {
+                self.initialized.store(true, Ordering::Release);
+            })
+        })
+    }
+
+    /// Get the reference to the underlying value, without checking if the cell
+    /// is initialized.
+    ///
+    /// # Safety
+    ///
+    /// Caller must ensure that the cell is in initialized state, and that
+    /// the contents are acquired by (synchronized to) this thread.
+    pub(crate) unsafe fn get_unchecked(&self) -> &T {
+        debug_assert!(self.is_initialized());
+        // SAFETY: The caller ensures that the value is initialized and access synchronized.
+        self.value.borrow(CriticalSection::new()).get().unwrap_unchecked()
+    }
+
+    #[inline]
+    pub(crate) fn get_mut(&mut self) -> Option<&mut T> {
+        self.value.get_mut().get_mut()
+    }
+
+    #[inline]
+    pub(crate) fn into_inner(self) -> Option<T> {
+        self.value.into_inner().into_inner()
+    }
+}
diff --git a/vendor/once_cell/src/imp_pl.rs b/vendor/once_cell/src/imp_pl.rs
new file mode 100644
index 0000000..37a8554
--- /dev/null
+++ b/vendor/once_cell/src/imp_pl.rs
@@ -0,0 +1,174 @@
+use std::{
+    cell::UnsafeCell,
+    panic::{RefUnwindSafe, UnwindSafe},
+    sync::atomic::{AtomicU8, Ordering},
+};
+
+pub(crate) struct OnceCell<T> {
+    state: AtomicU8,
+    value: UnsafeCell<Option<T>>,
+}
+
+const INCOMPLETE: u8 = 0x0;
+const RUNNING: u8 = 0x1;
+const COMPLETE: u8 = 0x2;
+
+// Why do we need `T: Send`?
+// Thread A creates a `OnceCell` and shares it with
+// scoped thread B, which fills the cell, which is
+// then destroyed by A. That is, destructor observes
+// a sent value.
+unsafe impl<T: Sync + Send> Sync for OnceCell<T> {}
+unsafe impl<T: Send> Send for OnceCell<T> {}
+
+impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
+impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}
+
+impl<T> OnceCell<T> {
+    pub(crate) const fn new() -> OnceCell<T> {
+        OnceCell { state: AtomicU8::new(INCOMPLETE), value: UnsafeCell::new(None) }
+    }
+
+    pub(crate) const fn with_value(value: T) -> OnceCell<T> {
+        OnceCell { state: AtomicU8::new(COMPLETE), value: UnsafeCell::new(Some(value)) }
+    }
+
+    /// Safety: synchronizes with store to value via Release/Acquire.
+    #[inline]
+    pub(crate) fn is_initialized(&self) -> bool {
+        self.state.load(Ordering::Acquire) == COMPLETE
+    }
+
+    /// Safety: synchronizes with store to value via `is_initialized` or mutex
+    /// lock/unlock, writes value only once because of the mutex.
+    #[cold]
+    pub(crate) fn initialize<F, E>(&self, f: F) -> Result<(), E>
+    where
+        F: FnOnce() -> Result<T, E>,
+    {
+        let mut f = Some(f);
+        let mut res: Result<(), E> = Ok(());
+        let slot: *mut Option<T> = self.value.get();
+        initialize_inner(&self.state, &mut || {
+            // We are calling user-supplied function and need to be careful.
+            // - if it returns Err, we unlock mutex and return without touching anything
+            // - if it panics, we unlock mutex and propagate panic without touching anything
+            // - if it calls `set` or `get_or_try_init` re-entrantly, we get a deadlock on
+            //   mutex, which is important for safety. We *could* detect this and panic,
+            //   but that is more complicated
+            // - finally, if it returns Ok, we store the value and store the flag with
+            //   `Release`, which synchronizes with `Acquire`s.
+            let f = unsafe { f.take().unwrap_unchecked() };
+            match f() {
+                Ok(value) => unsafe {
+                    // Safe b/c we have a unique access and no panic may happen
+                    // until the cell is marked as initialized.
+                    debug_assert!((*slot).is_none());
+                    *slot = Some(value);
+                    true
+                },
+                Err(err) => {
+                    res = Err(err);
+                    false
+                }
+            }
+        });
+        res
+    }
+
+    #[cold]
+    pub(crate) fn wait(&self) {
+        let key = &self.state as *const _ as usize;
+        unsafe {
+            parking_lot_core::park(
+                key,
+                || self.state.load(Ordering::Acquire) != COMPLETE,
+                || (),
+                |_, _| (),
+                parking_lot_core::DEFAULT_PARK_TOKEN,
+                None,
+            );
+        }
+    }
+
+    /// Get the reference to the underlying value, without checking if the cell
+    /// is initialized.
+    ///
+    /// # Safety
+    ///
+    /// Caller must ensure that the cell is in initialized state, and that
+    /// the contents are acquired by (synchronized to) this thread.
+    pub(crate) unsafe fn get_unchecked(&self) -> &T {
+        debug_assert!(self.is_initialized());
+        let slot = &*self.value.get();
+        slot.as_ref().unwrap_unchecked()
+    }
+
+    /// Gets the mutable reference to the underlying value.
+    /// Returns `None` if the cell is empty.
+    pub(crate) fn get_mut(&mut self) -> Option<&mut T> {
+        // Safe b/c we have an exclusive access
+        let slot: &mut Option<T> = unsafe { &mut *self.value.get() };
+        slot.as_mut()
+    }
+
+    /// Consumes this `OnceCell`, returning the wrapped value.
+    /// Returns `None` if the cell was empty.
+    pub(crate) fn into_inner(self) -> Option<T> {
+        self.value.into_inner()
+    }
+}
+
+struct Guard<'a> {
+    state: &'a AtomicU8,
+    new_state: u8,
+}
+
+impl<'a> Drop for Guard<'a> {
+    fn drop(&mut self) {
+        self.state.store(self.new_state, Ordering::Release);
+        unsafe {
+            let key = self.state as *const AtomicU8 as usize;
+            parking_lot_core::unpark_all(key, parking_lot_core::DEFAULT_UNPARK_TOKEN);
+        }
+    }
+}
+
+// Note: this is intentionally monomorphic
+#[inline(never)]
+fn initialize_inner(state: &AtomicU8, init: &mut dyn FnMut() -> bool) {
+    loop {
+        let exchange =
+            state.compare_exchange_weak(INCOMPLETE, RUNNING, Ordering::Acquire, Ordering::Acquire);
+        match exchange {
+            Ok(_) => {
+                let mut guard = Guard { state, new_state: INCOMPLETE };
+                if init() {
+                    guard.new_state = COMPLETE;
+                }
+                return;
+            }
+            Err(COMPLETE) => return,
+            Err(RUNNING) => unsafe {
+                let key = state as *const AtomicU8 as usize;
+                parking_lot_core::park(
+                    key,
+                    || state.load(Ordering::Relaxed) == RUNNING,
+                    || (),
+                    |_, _| (),
+                    parking_lot_core::DEFAULT_PARK_TOKEN,
+                    None,
+                );
+            },
+            Err(INCOMPLETE) => (),
+            Err(_) => debug_assert!(false),
+        }
+    }
+}
+
+#[test]
+fn test_size() {
+    use std::mem::size_of;
+
+    assert_eq!(size_of::<OnceCell<bool>>(), 1 * size_of::<bool>() + size_of::<u8>());
+}
diff --git a/vendor/once_cell/src/imp_std.rs b/vendor/once_cell/src/imp_std.rs
new file mode 100644
index 0000000..3b9e6d2
--- /dev/null
+++ b/vendor/once_cell/src/imp_std.rs
@@ -0,0 +1,415 @@
+// There's a lot of scary concurrent code in this module, but it is copied from
+// `std::sync::Once` with two changes:
+//   * no poisoning
+//   * init function can fail
+
+use std::{
+    cell::{Cell, UnsafeCell},
+    panic::{RefUnwindSafe, UnwindSafe},
+    sync::atomic::{AtomicBool, AtomicPtr, Ordering},
+    thread::{self, Thread},
+};
+
+#[derive(Debug)]
+pub(crate) struct OnceCell<T> {
+    // This `queue` field is the core of the implementation. It encodes two
+    // pieces of information:
+    //
+    // * The current state of the cell (`INCOMPLETE`, `RUNNING`, `COMPLETE`)
+    // * Linked list of threads waiting for the current cell.
+    //
+    // State is encoded in two low bits. Only `INCOMPLETE` and `RUNNING` states
+    // allow waiters.
+    queue: AtomicPtr<Waiter>,
+    value: UnsafeCell<Option<T>>,
+}
+
+// Why do we need `T: Send`?
+// Thread A creates a `OnceCell` and shares it with
+// scoped thread B, which fills the cell, which is
+// then destroyed by A. That is, destructor observes
+// a sent value.
+unsafe impl<T: Sync + Send> Sync for OnceCell<T> {}
+unsafe impl<T: Send> Send for OnceCell<T> {}
+
+impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
+impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}
+
+impl<T> OnceCell<T> {
+    pub(crate) const fn new() -> OnceCell<T> {
+        OnceCell { queue: AtomicPtr::new(INCOMPLETE_PTR), value: UnsafeCell::new(None) }
+    }
+
+    pub(crate) const fn with_value(value: T) -> OnceCell<T> {
+        OnceCell { queue: AtomicPtr::new(COMPLETE_PTR), value: UnsafeCell::new(Some(value)) }
+    }
+
+    /// Safety: synchronizes with store to value via Release/(Acquire|SeqCst).
+    #[inline]
+    pub(crate) fn is_initialized(&self) -> bool {
+        // An `Acquire` load is enough because that makes all the initialization
+        // operations visible to us, and, this being a fast path, weaker
+        // ordering helps with performance. This `Acquire` synchronizes with
+        // `SeqCst` operations on the slow path.
+        self.queue.load(Ordering::Acquire) == COMPLETE_PTR
+    }
+
+    /// Safety: synchronizes with store to value via SeqCst read from state,
+    /// writes value only once because we never get to INCOMPLETE state after a
+    /// successful write.
+    #[cold]
+    pub(crate) fn initialize<F, E>(&self, f: F) -> Result<(), E>
+    where
+        F: FnOnce() -> Result<T, E>,
+    {
+        let mut f = Some(f);
+        let mut res: Result<(), E> = Ok(());
+        let slot: *mut Option<T> = self.value.get();
+        initialize_or_wait(
+            &self.queue,
+            Some(&mut || {
+                let f = unsafe { f.take().unwrap_unchecked() };
+                match f() {
+                    Ok(value) => {
+                        unsafe { *slot = Some(value) };
+                        true
+                    }
+                    Err(err) => {
+                        res = Err(err);
+                        false
+                    }
+                }
+            }),
+        );
+        res
+    }
+
+    #[cold]
+    pub(crate) fn wait(&self) {
+        initialize_or_wait(&self.queue, None);
+    }
+
+    /// Get the reference to the underlying value, without checking if the cell
+    /// is initialized.
+    ///
+    /// # Safety
+    ///
+    /// Caller must ensure that the cell is in initialized state, and that
+    /// the contents are acquired by (synchronized to) this thread.
+    pub(crate) unsafe fn get_unchecked(&self) -> &T {
+        debug_assert!(self.is_initialized());
+        let slot = &*self.value.get();
+        slot.as_ref().unwrap_unchecked()
+    }
+
+    /// Gets the mutable reference to the underlying value.
+    /// Returns `None` if the cell is empty.
+    pub(crate) fn get_mut(&mut self) -> Option<&mut T> {
+        // Safe b/c we have a unique access.
+        unsafe { &mut *self.value.get() }.as_mut()
+    }
+
+    /// Consumes this `OnceCell`, returning the wrapped value.
+    /// Returns `None` if the cell was empty.
+    #[inline]
+    pub(crate) fn into_inner(self) -> Option<T> {
+        // Because `into_inner` takes `self` by value, the compiler statically
+        // verifies that it is not currently borrowed.
+        // So, it is safe to move out `Option<T>`.
+        self.value.into_inner()
+    }
+}
+
+// Three states that a OnceCell can be in, encoded into the lower bits of `queue` in
+// the OnceCell structure.
+const INCOMPLETE: usize = 0x0;
+const RUNNING: usize = 0x1;
+const COMPLETE: usize = 0x2;
+const INCOMPLETE_PTR: *mut Waiter = INCOMPLETE as *mut Waiter;
+const COMPLETE_PTR: *mut Waiter = COMPLETE as *mut Waiter;
+
+// Mask to learn about the state. All other bits are the queue of waiters if
+// this is in the RUNNING state.
+const STATE_MASK: usize = 0x3;
+
+/// Representation of a node in the linked list of waiters in the RUNNING state.
+/// A waiters is stored on the stack of the waiting threads.
+#[repr(align(4))] // Ensure the two lower bits are free to use as state bits.
+struct Waiter {
+    thread: Cell<Option<Thread>>,
+    signaled: AtomicBool,
+    next: *mut Waiter,
+}
+
+/// Drains and notifies the queue of waiters on drop.
+struct Guard<'a> {
+    queue: &'a AtomicPtr<Waiter>,
+    new_queue: *mut Waiter,
+}
+
+impl Drop for Guard<'_> {
+    fn drop(&mut self) {
+        let queue = self.queue.swap(self.new_queue, Ordering::AcqRel);
+
+        let state = strict::addr(queue) & STATE_MASK;
+        assert_eq!(state, RUNNING);
+
+        unsafe {
+            let mut waiter = strict::map_addr(queue, |q| q & !STATE_MASK);
+            while !waiter.is_null() {
+                let next = (*waiter).next;
+                let thread = (*waiter).thread.take().unwrap();
+                (*waiter).signaled.store(true, Ordering::Release);
+                waiter = next;
+                thread.unpark();
+            }
+        }
+    }
+}
+
+// Corresponds to `std::sync::Once::call_inner`.
+//
+// Originally copied from std, but since modified to remove poisoning and to
+// support wait.
+//
+// Note: this is intentionally monomorphic
+#[inline(never)]
+fn initialize_or_wait(queue: &AtomicPtr<Waiter>, mut init: Option<&mut dyn FnMut() -> bool>) {
+    let mut curr_queue = queue.load(Ordering::Acquire);
+
+    loop {
+        let curr_state = strict::addr(curr_queue) & STATE_MASK;
+        match (curr_state, &mut init) {
+            (COMPLETE, _) => return,
+            (INCOMPLETE, Some(init)) => {
+                let exchange = queue.compare_exchange(
+                    curr_queue,
+                    strict::map_addr(curr_queue, |q| (q & !STATE_MASK) | RUNNING),
+                    Ordering::Acquire,
+                    Ordering::Acquire,
+                );
+                if let Err(new_queue) = exchange {
+                    curr_queue = new_queue;
+                    continue;
+                }
+                let mut guard = Guard { queue, new_queue: INCOMPLETE_PTR };
+                if init() {
+                    guard.new_queue = COMPLETE_PTR;
+                }
+                return;
+            }
+            (INCOMPLETE, None) | (RUNNING, _) => {
+                wait(queue, curr_queue);
+                curr_queue = queue.load(Ordering::Acquire);
+            }
+            _ => debug_assert!(false),
+        }
+    }
+}
+
+fn wait(queue: &AtomicPtr<Waiter>, mut curr_queue: *mut Waiter) {
+    let curr_state = strict::addr(curr_queue) & STATE_MASK;
+    loop {
+        let node = Waiter {
+            thread: Cell::new(Some(thread::current())),
+            signaled: AtomicBool::new(false),
+            next: strict::map_addr(curr_queue, |q| q & !STATE_MASK),
+        };
+        let me = &node as *const Waiter as *mut Waiter;
+
+        let exchange = queue.compare_exchange(
+            curr_queue,
+            strict::map_addr(me, |q| q | curr_state),
+            Ordering::Release,
+            Ordering::Relaxed,
+        );
+        if let Err(new_queue) = exchange {
+            if strict::addr(new_queue) & STATE_MASK != curr_state {
+                return;
+            }
+            curr_queue = new_queue;
+            continue;
+        }
+
+        while !node.signaled.load(Ordering::Acquire) {
+            thread::park();
+        }
+        break;
+    }
+}
+
+// Polyfill of strict provenance from https://crates.io/crates/sptr.
+//
+// Use free-standing function rather than a trait to keep things simple and
+// avoid any potential conflicts with future stabile std API.
+mod strict {
+    #[must_use]
+    #[inline]
+    pub(crate) fn addr<T>(ptr: *mut T) -> usize
+    where
+        T: Sized,
+    {
+        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
+        // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
+        // provenance).
+        unsafe { core::mem::transmute(ptr) }
+    }
+
+    #[must_use]
+    #[inline]
+    pub(crate) fn with_addr<T>(ptr: *mut T, addr: usize) -> *mut T
+    where
+        T: Sized,
+    {
+        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
+        //
+        // In the mean-time, this operation is defined to be "as if" it was
+        // a wrapping_offset, so we can emulate it as such. This should properly
+        // restore pointer provenance even under today's compiler.
+        let self_addr = self::addr(ptr) as isize;
+        let dest_addr = addr as isize;
+        let offset = dest_addr.wrapping_sub(self_addr);
+
+        // This is the canonical desugarring of this operation,
+        // but `pointer::cast` was only stabilized in 1.38.
+        // self.cast::<u8>().wrapping_offset(offset).cast::<T>()
+        (ptr as *mut u8).wrapping_offset(offset) as *mut T
+    }
+
+    #[must_use]
+    #[inline]
+    pub(crate) fn map_addr<T>(ptr: *mut T, f: impl FnOnce(usize) -> usize) -> *mut T
+    where
+        T: Sized,
+    {
+        self::with_addr(ptr, f(addr(ptr)))
+    }
+}
+
+// These test are snatched from std as well.
+#[cfg(test)]
+mod tests {
+    use std::panic;
+    use std::{sync::mpsc::channel, thread};
+
+    use super::OnceCell;
+
+    impl<T> OnceCell<T> {
+        fn init(&self, f: impl FnOnce() -> T) {
+            enum Void {}
+            let _ = self.initialize(|| Ok::<T, Void>(f()));
+        }
+    }
+
+    #[test]
+    fn smoke_once() {
+        static O: OnceCell<()> = OnceCell::new();
+        let mut a = 0;
+        O.init(|| a += 1);
+        assert_eq!(a, 1);
+        O.init(|| a += 1);
+        assert_eq!(a, 1);
+    }
+
+    #[test]
+    fn stampede_once() {
+        static O: OnceCell<()> = OnceCell::new();
+        static mut RUN: bool = false;
+
+        let (tx, rx) = channel();
+        for _ in 0..10 {
+            let tx = tx.clone();
+            thread::spawn(move || {
+                for _ in 0..4 {
+                    thread::yield_now()
+                }
+                unsafe {
+                    O.init(|| {
+                        assert!(!RUN);
+                        RUN = true;
+                    });
+                    assert!(RUN);
+                }
+                tx.send(()).unwrap();
+            });
+        }
+
+        unsafe {
+            O.init(|| {
+                assert!(!RUN);
+                RUN = true;
+            });
+            assert!(RUN);
+        }
+
+        for _ in 0..10 {
+            rx.recv().unwrap();
+        }
+    }
+
+    #[test]
+    fn poison_bad() {
+        static O: OnceCell<()> = OnceCell::new();
+
+        // poison the once
+        let t = panic::catch_unwind(|| {
+            O.init(|| panic!());
+        });
+        assert!(t.is_err());
+
+        // we can subvert poisoning, however
+        let mut called = false;
+        O.init(|| {
+            called = true;
+        });
+        assert!(called);
+
+        // once any success happens, we stop propagating the poison
+        O.init(|| {});
+    }
+
+    #[test]
+    fn wait_for_force_to_finish() {
+        static O: OnceCell<()> = OnceCell::new();
+
+        // poison the once
+        let t = panic::catch_unwind(|| {
+            O.init(|| panic!());
+        });
+        assert!(t.is_err());
+
+        // make sure someone's waiting inside the once via a force
+        let (tx1, rx1) = channel();
+        let (tx2, rx2) = channel();
+        let t1 = thread::spawn(move || {
+            O.init(|| {
+                tx1.send(()).unwrap();
+                rx2.recv().unwrap();
+            });
+        });
+
+        rx1.recv().unwrap();
+
+        // put another waiter on the once
+        let t2 = thread::spawn(|| {
+            let mut called = false;
+            O.init(|| {
+                called = true;
+            });
+            assert!(!called);
+        });
+
+        tx2.send(()).unwrap();
+
+        assert!(t1.join().is_ok());
+        assert!(t2.join().is_ok());
+    }
+
+    #[test]
+    #[cfg(target_pointer_width = "64")]
+    fn test_size() {
+        use std::mem::size_of;
+
+        assert_eq!(size_of::<OnceCell<u32>>(), 4 * size_of::<u32>());
+    }
+}
diff --git a/vendor/once_cell/src/lib.rs b/vendor/once_cell/src/lib.rs
new file mode 100644
index 0000000..db7e19a
--- /dev/null
+++ b/vendor/once_cell/src/lib.rs
@@ -0,0 +1,1414 @@
+//! # Overview
+//!
+//! `once_cell` provides two new cell-like types, [`unsync::OnceCell`] and
+//! [`sync::OnceCell`]. A `OnceCell` might store arbitrary non-`Copy` types, can
+//! be assigned to at most once and provides direct access to the stored
+//! contents. The core API looks *roughly* like this (and there's much more
+//! inside, read on!):
+//!
+//! ```rust,ignore
+//! impl<T> OnceCell<T> {
+//!     const fn new() -> OnceCell<T> { ... }
+//!     fn set(&self, value: T) -> Result<(), T> { ... }
+//!     fn get(&self) -> Option<&T> { ... }
+//! }
+//! ```
+//!
+//! Note that, like with [`RefCell`] and [`Mutex`], the `set` method requires
+//! only a shared reference. Because of the single assignment restriction `get`
+//! can return a `&T` instead of `Ref<T>` or `MutexGuard<T>`.
+//!
+//! The `sync` flavor is thread-safe (that is, implements the [`Sync`] trait),
+//! while the `unsync` one is not.
+//!
+//! [`unsync::OnceCell`]: unsync/struct.OnceCell.html
+//! [`sync::OnceCell`]: sync/struct.OnceCell.html
+//! [`RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
+//! [`Mutex`]: https://doc.rust-lang.org/std/sync/struct.Mutex.html
+//! [`Sync`]: https://doc.rust-lang.org/std/marker/trait.Sync.html
+//!
+//! # Recipes
+//!
+//! `OnceCell` might be useful for a variety of patterns.
+//!
+//! ## Safe Initialization of Global Data
+//!
+//! ```rust
+//! use std::{env, io};
+//!
+//! use once_cell::sync::OnceCell;
+//!
+//! #[derive(Debug)]
+//! pub struct Logger {
+//!     // ...
+//! }
+//! static INSTANCE: OnceCell<Logger> = OnceCell::new();
+//!
+//! impl Logger {
+//!     pub fn global() -> &'static Logger {
+//!         INSTANCE.get().expect("logger is not initialized")
+//!     }
+//!
+//!     fn from_cli(args: env::Args) -> Result<Logger, std::io::Error> {
+//!        // ...
+//! #      Ok(Logger {})
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let logger = Logger::from_cli(env::args()).unwrap();
+//!     INSTANCE.set(logger).unwrap();
+//!     // use `Logger::global()` from now on
+//! }
+//! ```
+//!
+//! ## Lazy Initialized Global Data
+//!
+//! This is essentially the `lazy_static!` macro, but without a macro.
+//!
+//! ```rust
+//! use std::{sync::Mutex, collections::HashMap};
+//!
+//! use once_cell::sync::OnceCell;
+//!
+//! fn global_data() -> &'static Mutex<HashMap<i32, String>> {
+//!     static INSTANCE: OnceCell<Mutex<HashMap<i32, String>>> = OnceCell::new();
+//!     INSTANCE.get_or_init(|| {
+//!         let mut m = HashMap::new();
+//!         m.insert(13, "Spica".to_string());
+//!         m.insert(74, "Hoyten".to_string());
+//!         Mutex::new(m)
+//!     })
+//! }
+//! ```
+//!
+//! There are also the [`sync::Lazy`] and [`unsync::Lazy`] convenience types to
+//! streamline this pattern:
+//!
+//! ```rust
+//! use std::{sync::Mutex, collections::HashMap};
+//! use once_cell::sync::Lazy;
+//!
+//! static GLOBAL_DATA: Lazy<Mutex<HashMap<i32, String>>> = Lazy::new(|| {
+//!     let mut m = HashMap::new();
+//!     m.insert(13, "Spica".to_string());
+//!     m.insert(74, "Hoyten".to_string());
+//!     Mutex::new(m)
+//! });
+//!
+//! fn main() {
+//!     println!("{:?}", GLOBAL_DATA.lock().unwrap());
+//! }
+//! ```
+//!
+//! Note that the variable that holds `Lazy` is declared as `static`, *not*
+//! `const`. This is important: using `const` instead compiles, but works wrong.
+//!
+//! [`sync::Lazy`]: sync/struct.Lazy.html
+//! [`unsync::Lazy`]: unsync/struct.Lazy.html
+//!
+//! ## General purpose lazy evaluation
+//!
+//! Unlike `lazy_static!`, `Lazy` works with local variables.
+//!
+//! ```rust
+//! use once_cell::unsync::Lazy;
+//!
+//! fn main() {
+//!     let ctx = vec![1, 2, 3];
+//!     let thunk = Lazy::new(|| {
+//!         ctx.iter().sum::<i32>()
+//!     });
+//!     assert_eq!(*thunk, 6);
+//! }
+//! ```
+//!
+//! If you need a lazy field in a struct, you probably should use `OnceCell`
+//! directly, because that will allow you to access `self` during
+//! initialization.
+//!
+//! ```rust
+//! use std::{fs, path::PathBuf};
+//!
+//! use once_cell::unsync::OnceCell;
+//!
+//! struct Ctx {
+//!     config_path: PathBuf,
+//!     config: OnceCell<String>,
+//! }
+//!
+//! impl Ctx {
+//!     pub fn get_config(&self) -> Result<&str, std::io::Error> {
+//!         let cfg = self.config.get_or_try_init(|| {
+//!             fs::read_to_string(&self.config_path)
+//!         })?;
+//!         Ok(cfg.as_str())
+//!     }
+//! }
+//! ```
+//!
+//! ## Lazily Compiled Regex
+//!
+//! This is a `regex!` macro which takes a string literal and returns an
+//! *expression* that evaluates to a `&'static Regex`:
+//!
+//! ```
+//! macro_rules! regex {
+//!     ($re:literal $(,)?) => {{
+//!         static RE: once_cell::sync::OnceCell<regex::Regex> = once_cell::sync::OnceCell::new();
+//!         RE.get_or_init(|| regex::Regex::new($re).unwrap())
+//!     }};
+//! }
+//! ```
+//!
+//! This macro can be useful to avoid the "compile regex on every loop
+//! iteration" problem.
+//!
+//! ## Runtime `include_bytes!`
+//!
+//! The `include_bytes` macro is useful to include test resources, but it slows
+//! down test compilation a lot. An alternative is to load the resources at
+//! runtime:
+//!
+//! ```
+//! use std::path::Path;
+//!
+//! use once_cell::sync::OnceCell;
+//!
+//! pub struct TestResource {
+//!     path: &'static str,
+//!     cell: OnceCell<Vec<u8>>,
+//! }
+//!
+//! impl TestResource {
+//!     pub const fn new(path: &'static str) -> TestResource {
+//!         TestResource { path, cell: OnceCell::new() }
+//!     }
+//!     pub fn bytes(&self) -> &[u8] {
+//!         self.cell.get_or_init(|| {
+//!             let dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+//!             let path = Path::new(dir.as_str()).join(self.path);
+//!             std::fs::read(&path).unwrap_or_else(|_err| {
+//!                 panic!("failed to load test resource: {}", path.display())
+//!             })
+//!         }).as_slice()
+//!     }
+//! }
+//!
+//! static TEST_IMAGE: TestResource = TestResource::new("test_data/lena.png");
+//!
+//! #[test]
+//! fn test_sobel_filter() {
+//!     let rgb: &[u8] = TEST_IMAGE.bytes();
+//!     // ...
+//! # drop(rgb);
+//! }
+//! ```
+//!
+//! ## `lateinit`
+//!
+//! `LateInit` type for delayed initialization. It is reminiscent of Kotlin's
+//! `lateinit` keyword and allows construction of cyclic data structures:
+//!
+//!
+//! ```
+//! use once_cell::sync::OnceCell;
+//!
+//! pub struct LateInit<T> { cell: OnceCell<T> }
+//!
+//! impl<T> LateInit<T> {
+//!     pub fn init(&self, value: T) {
+//!         assert!(self.cell.set(value).is_ok())
+//!     }
+//! }
+//!
+//! impl<T> Default for LateInit<T> {
+//!     fn default() -> Self { LateInit { cell: OnceCell::default() } }
+//! }
+//!
+//! impl<T> std::ops::Deref for LateInit<T> {
+//!     type Target = T;
+//!     fn deref(&self) -> &T {
+//!         self.cell.get().unwrap()
+//!     }
+//! }
+//!
+//! #[derive(Default)]
+//! struct A<'a> {
+//!     b: LateInit<&'a B<'a>>,
+//! }
+//!
+//! #[derive(Default)]
+//! struct B<'a> {
+//!     a: LateInit<&'a A<'a>>
+//! }
+//!
+//!
+//! fn build_cycle() {
+//!     let a = A::default();
+//!     let b = B::default();
+//!     a.b.init(&b);
+//!     b.a.init(&a);
+//!
+//!     let _a = &a.b.a.b.a;
+//! }
+//! ```
+//!
+//! # Comparison with std
+//!
+//! |`!Sync` types         | Access Mode            | Drawbacks                                     |
+//! |----------------------|------------------------|-----------------------------------------------|
+//! |`Cell<T>`             | `T`                    | requires `T: Copy` for `get`                  |
+//! |`RefCell<T>`          | `RefMut<T>` / `Ref<T>` | may panic at runtime                          |
+//! |`unsync::OnceCell<T>` | `&T`                   | assignable only once                          |
+//!
+//! |`Sync` types          | Access Mode            | Drawbacks                                     |
+//! |----------------------|------------------------|-----------------------------------------------|
+//! |`AtomicT`             | `T`                    | works only with certain `Copy` types          |
+//! |`Mutex<T>`            | `MutexGuard<T>`        | may deadlock at runtime, may block the thread |
+//! |`sync::OnceCell<T>`   | `&T`                   | assignable only once, may block the thread    |
+//!
+//! Technically, calling `get_or_init` will also cause a panic or a deadlock if
+//! it recursively calls itself. However, because the assignment can happen only
+//! once, such cases should be more rare than equivalents with `RefCell` and
+//! `Mutex`.
+//!
+//! # Minimum Supported `rustc` Version
+//!
+//! This crate's minimum supported `rustc` version is `1.56.0`.
+//!
+//! If only the `std` feature is enabled, MSRV will be updated conservatively,
+//! supporting at least latest 8 versions of the compiler. When using other
+//! features, like `parking_lot`, MSRV might be updated more frequently, up to
+//! the latest stable. In both cases, increasing MSRV is *not* considered a
+//! semver-breaking change.
+//!
+//! # Implementation details
+//!
+//! The implementation is based on the
+//! [`lazy_static`](https://github.com/rust-lang-nursery/lazy-static.rs/) and
+//! [`lazy_cell`](https://github.com/indiv0/lazycell/) crates and
+//! [`std::sync::Once`]. In some sense, `once_cell` just streamlines and unifies
+//! those APIs.
+//!
+//! To implement a sync flavor of `OnceCell`, this crates uses either a custom
+//! re-implementation of `std::sync::Once` or `parking_lot::Mutex`. This is
+//! controlled by the `parking_lot` feature (disabled by default). Performance
+//! is the same for both cases, but the `parking_lot` based `OnceCell<T>` is
+//! smaller by up to 16 bytes.
+//!
+//! This crate uses `unsafe`.
+//!
+//! [`std::sync::Once`]: https://doc.rust-lang.org/std/sync/struct.Once.html
+//!
+//! # F.A.Q.
+//!
+//! **Should I use the sync or unsync flavor?**
+//!
+//! Because Rust compiler checks thread safety for you, it's impossible to
+//! accidentally use `unsync` where `sync` is required. So, use `unsync` in
+//! single-threaded code and `sync` in multi-threaded. It's easy to switch
+//! between the two if code becomes multi-threaded later.
+//!
+//! At the moment, `unsync` has an additional benefit that reentrant
+//! initialization causes a panic, which might be easier to debug than a
+//! deadlock.
+//!
+//! **Does this crate support async?**
+//!
+//! No, but you can use
+//! [`async_once_cell`](https://crates.io/crates/async_once_cell) instead.
+//!
+//! **Does this crate support `no_std`?**
+//!
+//! Yes, but with caveats. `OnceCell` is a synchronization primitive which
+//! _semantically_ relies on blocking. `OnceCell` guarantees that at most one
+//! `f` will be called to compute the value. If two threads of execution call
+//! `get_or_init` concurrently, one of them has to wait.
+//!
+//! Waiting fundamentally requires OS support. Execution environment needs to
+//! understand who waits on whom to prevent deadlocks due to priority inversion.
+//! You _could_ make code to compile by blindly using pure spinlocks, but the
+//! runtime behavior would be subtly wrong.
+//!
+//! Given these constraints, `once_cell` provides the following options:
+//!
+//! - The `race` module provides similar, but distinct synchronization primitive
+//!   which is compatible with `no_std`. With `race`, the `f` function can be
+//!   called multiple times by different threads, but only one thread will win
+//!   to install the value.
+//! - `critical-section` feature (with a `-`, not `_`) uses `critical_section`
+//!   to implement blocking.
+//!
+//! **Can I bring my own mutex?**
+//!
+//! There is [generic_once_cell](https://crates.io/crates/generic_once_cell) to
+//! allow just that.
+//!
+//! **Should I use `std::cell::OnceCell`, `once_cell`, or `lazy_static`?**
+//!
+//! If you can use `std` version (your MSRV is at least 1.70, and you don't need
+//! extra features `once_cell` provides), use `std`. Otherwise, use `once_cell`.
+//! Don't use `lazy_static`.
+//!
+//! # Related crates
+//!
+//! * Most of this crate's functionality is available in `std` starting with
+//!   Rust 1.70. See `std::cell::OnceCell` and `std::sync::OnceLock`.
+//! * [double-checked-cell](https://github.com/niklasf/double-checked-cell)
+//! * [lazy-init](https://crates.io/crates/lazy-init)
+//! * [lazycell](https://crates.io/crates/lazycell)
+//! * [mitochondria](https://crates.io/crates/mitochondria)
+//! * [lazy_static](https://crates.io/crates/lazy_static)
+//! * [async_once_cell](https://crates.io/crates/async_once_cell)
+//! * [generic_once_cell](https://crates.io/crates/generic_once_cell) (bring
+//!   your own mutex)
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(feature = "alloc")]
+extern crate alloc;
+
+#[cfg(all(feature = "critical-section", not(feature = "std")))]
+#[path = "imp_cs.rs"]
+mod imp;
+
+#[cfg(all(feature = "std", feature = "parking_lot"))]
+#[path = "imp_pl.rs"]
+mod imp;
+
+#[cfg(all(feature = "std", not(feature = "parking_lot")))]
+#[path = "imp_std.rs"]
+mod imp;
+
+/// Single-threaded version of `OnceCell`.
+pub mod unsync {
+    use core::{
+        cell::{Cell, UnsafeCell},
+        fmt, mem,
+        ops::{Deref, DerefMut},
+        panic::{RefUnwindSafe, UnwindSafe},
+    };
+
+    /// A cell which can be written to only once. It is not thread safe.
+    ///
+    /// Unlike [`std::cell::RefCell`], a `OnceCell` provides simple `&`
+    /// references to the contents.
+    ///
+    /// [`std::cell::RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
+    ///
+    /// # Example
+    /// ```
+    /// use once_cell::unsync::OnceCell;
+    ///
+    /// let cell = OnceCell::new();
+    /// assert!(cell.get().is_none());
+    ///
+    /// let value: &String = cell.get_or_init(|| {
+    ///     "Hello, World!".to_string()
+    /// });
+    /// assert_eq!(value, "Hello, World!");
+    /// assert!(cell.get().is_some());
+    /// ```
+    pub struct OnceCell<T> {
+        // Invariant: written to at most once.
+        inner: UnsafeCell<Option<T>>,
+    }
+
+    // Similarly to a `Sync` bound on `sync::OnceCell`, we can use
+    // `&unsync::OnceCell` to sneak a `T` through `catch_unwind`,
+    // by initializing the cell in closure and extracting the value in the
+    // `Drop`.
+    impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
+    impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}
+
+    impl<T> Default for OnceCell<T> {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+
+    impl<T: fmt::Debug> fmt::Debug for OnceCell<T> {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            match self.get() {
+                Some(v) => f.debug_tuple("OnceCell").field(v).finish(),
+                None => f.write_str("OnceCell(Uninit)"),
+            }
+        }
+    }
+
+    impl<T: Clone> Clone for OnceCell<T> {
+        fn clone(&self) -> OnceCell<T> {
+            match self.get() {
+                Some(value) => OnceCell::with_value(value.clone()),
+                None => OnceCell::new(),
+            }
+        }
+
+        fn clone_from(&mut self, source: &Self) {
+            match (self.get_mut(), source.get()) {
+                (Some(this), Some(source)) => this.clone_from(source),
+                _ => *self = source.clone(),
+            }
+        }
+    }
+
+    impl<T: PartialEq> PartialEq for OnceCell<T> {
+        fn eq(&self, other: &Self) -> bool {
+            self.get() == other.get()
+        }
+    }
+
+    impl<T: Eq> Eq for OnceCell<T> {}
+
+    impl<T> From<T> for OnceCell<T> {
+        fn from(value: T) -> Self {
+            OnceCell::with_value(value)
+        }
+    }
+
+    impl<T> OnceCell<T> {
+        /// Creates a new empty cell.
+        pub const fn new() -> OnceCell<T> {
+            OnceCell { inner: UnsafeCell::new(None) }
+        }
+
+        /// Creates a new initialized cell.
+        pub const fn with_value(value: T) -> OnceCell<T> {
+            OnceCell { inner: UnsafeCell::new(Some(value)) }
+        }
+
+        /// Gets a reference to the underlying value.
+        ///
+        /// Returns `None` if the cell is empty.
+        #[inline]
+        pub fn get(&self) -> Option<&T> {
+            // Safe due to `inner`'s invariant of being written to at most once.
+            // Had multiple writes to `inner` been allowed, a reference to the
+            // value we return now would become dangling by a write of a
+            // different value later.
+            unsafe { &*self.inner.get() }.as_ref()
+        }
+
+        /// Gets a mutable reference to the underlying value.
+        ///
+        /// Returns `None` if the cell is empty.
+        ///
+        /// This method is allowed to violate the invariant of writing to a `OnceCell`
+        /// at most once because it requires `&mut` access to `self`. As with all
+        /// interior mutability, `&mut` access permits arbitrary modification:
+        ///
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<u32> = OnceCell::new();
+        /// cell.set(92).unwrap();
+        /// *cell.get_mut().unwrap() = 93;
+        /// assert_eq!(cell.get(), Some(&93));
+        /// ```
+        #[inline]
+        pub fn get_mut(&mut self) -> Option<&mut T> {
+            // Safe because we have unique access
+            unsafe { &mut *self.inner.get() }.as_mut()
+        }
+
+        /// Sets the contents of this cell to `value`.
+        ///
+        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
+        /// full.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// assert!(cell.get().is_none());
+        ///
+        /// assert_eq!(cell.set(92), Ok(()));
+        /// assert_eq!(cell.set(62), Err(62));
+        ///
+        /// assert!(cell.get().is_some());
+        /// ```
+        pub fn set(&self, value: T) -> Result<(), T> {
+            match self.try_insert(value) {
+                Ok(_) => Ok(()),
+                Err((_, value)) => Err(value),
+            }
+        }
+
+        /// Like [`set`](Self::set), but also returns a reference to the final cell value.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// assert!(cell.get().is_none());
+        ///
+        /// assert_eq!(cell.try_insert(92), Ok(&92));
+        /// assert_eq!(cell.try_insert(62), Err((&92, 62)));
+        ///
+        /// assert!(cell.get().is_some());
+        /// ```
+        pub fn try_insert(&self, value: T) -> Result<&T, (&T, T)> {
+            if let Some(old) = self.get() {
+                return Err((old, value));
+            }
+
+            let slot = unsafe { &mut *self.inner.get() };
+            // This is the only place where we set the slot, no races
+            // due to reentrancy/concurrency are possible, and we've
+            // checked that slot is currently `None`, so this write
+            // maintains the `inner`'s invariant.
+            *slot = Some(value);
+            Ok(unsafe { slot.as_ref().unwrap_unchecked() })
+        }
+
+        /// Gets the contents of the cell, initializing it with `f`
+        /// if the cell was empty.
+        ///
+        /// # Panics
+        ///
+        /// If `f` panics, the panic is propagated to the caller, and the cell
+        /// remains uninitialized.
+        ///
+        /// It is an error to reentrantly initialize the cell from `f`. Doing
+        /// so results in a panic.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// let value = cell.get_or_init(|| 92);
+        /// assert_eq!(value, &92);
+        /// let value = cell.get_or_init(|| unreachable!());
+        /// assert_eq!(value, &92);
+        /// ```
+        pub fn get_or_init<F>(&self, f: F) -> &T
+        where
+            F: FnOnce() -> T,
+        {
+            enum Void {}
+            match self.get_or_try_init(|| Ok::<T, Void>(f())) {
+                Ok(val) => val,
+                Err(void) => match void {},
+            }
+        }
+
+        /// Gets the contents of the cell, initializing it with `f` if
+        /// the cell was empty. If the cell was empty and `f` failed, an
+        /// error is returned.
+        ///
+        /// # Panics
+        ///
+        /// If `f` panics, the panic is propagated to the caller, and the cell
+        /// remains uninitialized.
+        ///
+        /// It is an error to reentrantly initialize the cell from `f`. Doing
+        /// so results in a panic.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
+        /// assert!(cell.get().is_none());
+        /// let value = cell.get_or_try_init(|| -> Result<i32, ()> {
+        ///     Ok(92)
+        /// });
+        /// assert_eq!(value, Ok(&92));
+        /// assert_eq!(cell.get(), Some(&92))
+        /// ```
+        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
+        where
+            F: FnOnce() -> Result<T, E>,
+        {
+            if let Some(val) = self.get() {
+                return Ok(val);
+            }
+            let val = f()?;
+            // Note that *some* forms of reentrant initialization might lead to
+            // UB (see `reentrant_init` test). I believe that just removing this
+            // `assert`, while keeping `set/get` would be sound, but it seems
+            // better to panic, rather than to silently use an old value.
+            assert!(self.set(val).is_ok(), "reentrant init");
+            Ok(unsafe { self.get().unwrap_unchecked() })
+        }
+
+        /// Takes the value out of this `OnceCell`, moving it back to an uninitialized state.
+        ///
+        /// Has no effect and returns `None` if the `OnceCell` hasn't been initialized.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<String> = OnceCell::new();
+        /// assert_eq!(cell.take(), None);
+        ///
+        /// let mut cell = OnceCell::new();
+        /// cell.set("hello".to_string()).unwrap();
+        /// assert_eq!(cell.take(), Some("hello".to_string()));
+        /// assert_eq!(cell.get(), None);
+        /// ```
+        ///
+        /// This method is allowed to violate the invariant of writing to a `OnceCell`
+        /// at most once because it requires `&mut` access to `self`. As with all
+        /// interior mutability, `&mut` access permits arbitrary modification:
+        ///
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<u32> = OnceCell::new();
+        /// cell.set(92).unwrap();
+        /// cell = OnceCell::new();
+        /// ```
+        pub fn take(&mut self) -> Option<T> {
+            mem::take(self).into_inner()
+        }
+
+        /// Consumes the `OnceCell`, returning the wrapped value.
+        ///
+        /// Returns `None` if the cell was empty.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell: OnceCell<String> = OnceCell::new();
+        /// assert_eq!(cell.into_inner(), None);
+        ///
+        /// let cell = OnceCell::new();
+        /// cell.set("hello".to_string()).unwrap();
+        /// assert_eq!(cell.into_inner(), Some("hello".to_string()));
+        /// ```
+        pub fn into_inner(self) -> Option<T> {
+            // Because `into_inner` takes `self` by value, the compiler statically verifies
+            // that it is not currently borrowed. So it is safe to move out `Option<T>`.
+            self.inner.into_inner()
+        }
+    }
+
+    /// A value which is initialized on the first access.
+    ///
+    /// # Example
+    /// ```
+    /// use once_cell::unsync::Lazy;
+    ///
+    /// let lazy: Lazy<i32> = Lazy::new(|| {
+    ///     println!("initializing");
+    ///     92
+    /// });
+    /// println!("ready");
+    /// println!("{}", *lazy);
+    /// println!("{}", *lazy);
+    ///
+    /// // Prints:
+    /// //   ready
+    /// //   initializing
+    /// //   92
+    /// //   92
+    /// ```
+    pub struct Lazy<T, F = fn() -> T> {
+        cell: OnceCell<T>,
+        init: Cell<Option<F>>,
+    }
+
+    impl<T, F: RefUnwindSafe> RefUnwindSafe for Lazy<T, F> where OnceCell<T>: RefUnwindSafe {}
+
+    impl<T: fmt::Debug, F> fmt::Debug for Lazy<T, F> {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            f.debug_struct("Lazy").field("cell", &self.cell).field("init", &"..").finish()
+        }
+    }
+
+    impl<T, F> Lazy<T, F> {
+        /// Creates a new lazy value with the given initializing function.
+        ///
+        /// # Example
+        /// ```
+        /// # fn main() {
+        /// use once_cell::unsync::Lazy;
+        ///
+        /// let hello = "Hello, World!".to_string();
+        ///
+        /// let lazy = Lazy::new(|| hello.to_uppercase());
+        ///
+        /// assert_eq!(&*lazy, "HELLO, WORLD!");
+        /// # }
+        /// ```
+        pub const fn new(init: F) -> Lazy<T, F> {
+            Lazy { cell: OnceCell::new(), init: Cell::new(Some(init)) }
+        }
+
+        /// Consumes this `Lazy` returning the stored value.
+        ///
+        /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
+        pub fn into_value(this: Lazy<T, F>) -> Result<T, F> {
+            let cell = this.cell;
+            let init = this.init;
+            cell.into_inner().ok_or_else(|| {
+                init.take().unwrap_or_else(|| panic!("Lazy instance has previously been poisoned"))
+            })
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> Lazy<T, F> {
+        /// Forces the evaluation of this lazy value and returns a reference to
+        /// the result.
+        ///
+        /// This is equivalent to the `Deref` impl, but is explicit.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::Lazy;
+        ///
+        /// let lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::force(&lazy), &92);
+        /// assert_eq!(&*lazy, &92);
+        /// ```
+        pub fn force(this: &Lazy<T, F>) -> &T {
+            this.cell.get_or_init(|| match this.init.take() {
+                Some(f) => f(),
+                None => panic!("Lazy instance has previously been poisoned"),
+            })
+        }
+
+        /// Forces the evaluation of this lazy value and returns a mutable reference to
+        /// the result.
+        ///
+        /// This is equivalent to the `DerefMut` impl, but is explicit.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::Lazy;
+        ///
+        /// let mut lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::force_mut(&mut lazy), &92);
+        /// assert_eq!(*lazy, 92);
+        /// ```
+        pub fn force_mut(this: &mut Lazy<T, F>) -> &mut T {
+            if this.cell.get_mut().is_none() {
+                let value = match this.init.get_mut().take() {
+                    Some(f) => f(),
+                    None => panic!("Lazy instance has previously been poisoned"),
+                };
+                this.cell = OnceCell::with_value(value);
+            }
+            this.cell.get_mut().unwrap_or_else(|| unreachable!())
+        }
+
+        /// Gets the reference to the result of this lazy value if
+        /// it was initialized, otherwise returns `None`.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::Lazy;
+        ///
+        /// let lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::get(&lazy), None);
+        /// assert_eq!(&*lazy, &92);
+        /// assert_eq!(Lazy::get(&lazy), Some(&92));
+        /// ```
+        pub fn get(this: &Lazy<T, F>) -> Option<&T> {
+            this.cell.get()
+        }
+
+        /// Gets the mutable reference to the result of this lazy value if
+        /// it was initialized, otherwise returns `None`.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::unsync::Lazy;
+        ///
+        /// let mut lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::get_mut(&mut lazy), None);
+        /// assert_eq!(*lazy, 92);
+        /// assert_eq!(Lazy::get_mut(&mut lazy), Some(&mut 92));
+        /// ```
+        pub fn get_mut(this: &mut Lazy<T, F>) -> Option<&mut T> {
+            this.cell.get_mut()
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
+        type Target = T;
+        fn deref(&self) -> &T {
+            Lazy::force(self)
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> DerefMut for Lazy<T, F> {
+        fn deref_mut(&mut self) -> &mut T {
+            Lazy::force_mut(self)
+        }
+    }
+
+    impl<T: Default> Default for Lazy<T> {
+        /// Creates a new lazy value using `Default` as the initializing function.
+        fn default() -> Lazy<T> {
+            Lazy::new(T::default)
+        }
+    }
+}
+
+/// Thread-safe, blocking version of `OnceCell`.
+#[cfg(any(feature = "std", feature = "critical-section"))]
+pub mod sync {
+    use core::{
+        cell::Cell,
+        fmt, mem,
+        ops::{Deref, DerefMut},
+        panic::RefUnwindSafe,
+    };
+
+    use super::imp::OnceCell as Imp;
+
+    /// A thread-safe cell which can be written to only once.
+    ///
+    /// `OnceCell` provides `&` references to the contents without RAII guards.
+    ///
+    /// Reading a non-`None` value out of `OnceCell` establishes a
+    /// happens-before relationship with a corresponding write. For example, if
+    /// thread A initializes the cell with `get_or_init(f)`, and thread B
+    /// subsequently reads the result of this call, B also observes all the side
+    /// effects of `f`.
+    ///
+    /// # Example
+    /// ```
+    /// use once_cell::sync::OnceCell;
+    ///
+    /// static CELL: OnceCell<String> = OnceCell::new();
+    /// assert!(CELL.get().is_none());
+    ///
+    /// std::thread::spawn(|| {
+    ///     let value: &String = CELL.get_or_init(|| {
+    ///         "Hello, World!".to_string()
+    ///     });
+    ///     assert_eq!(value, "Hello, World!");
+    /// }).join().unwrap();
+    ///
+    /// let value: Option<&String> = CELL.get();
+    /// assert!(value.is_some());
+    /// assert_eq!(value.unwrap().as_str(), "Hello, World!");
+    /// ```
+    pub struct OnceCell<T>(Imp<T>);
+
+    impl<T> Default for OnceCell<T> {
+        fn default() -> OnceCell<T> {
+            OnceCell::new()
+        }
+    }
+
+    impl<T: fmt::Debug> fmt::Debug for OnceCell<T> {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            match self.get() {
+                Some(v) => f.debug_tuple("OnceCell").field(v).finish(),
+                None => f.write_str("OnceCell(Uninit)"),
+            }
+        }
+    }
+
+    impl<T: Clone> Clone for OnceCell<T> {
+        fn clone(&self) -> OnceCell<T> {
+            match self.get() {
+                Some(value) => Self::with_value(value.clone()),
+                None => Self::new(),
+            }
+        }
+
+        fn clone_from(&mut self, source: &Self) {
+            match (self.get_mut(), source.get()) {
+                (Some(this), Some(source)) => this.clone_from(source),
+                _ => *self = source.clone(),
+            }
+        }
+    }
+
+    impl<T> From<T> for OnceCell<T> {
+        fn from(value: T) -> Self {
+            Self::with_value(value)
+        }
+    }
+
+    impl<T: PartialEq> PartialEq for OnceCell<T> {
+        fn eq(&self, other: &OnceCell<T>) -> bool {
+            self.get() == other.get()
+        }
+    }
+
+    impl<T: Eq> Eq for OnceCell<T> {}
+
+    impl<T> OnceCell<T> {
+        /// Creates a new empty cell.
+        pub const fn new() -> OnceCell<T> {
+            OnceCell(Imp::new())
+        }
+
+        /// Creates a new initialized cell.
+        pub const fn with_value(value: T) -> OnceCell<T> {
+            OnceCell(Imp::with_value(value))
+        }
+
+        /// Gets the reference to the underlying value.
+        ///
+        /// Returns `None` if the cell is empty, or being initialized. This
+        /// method never blocks.
+        pub fn get(&self) -> Option<&T> {
+            if self.0.is_initialized() {
+                // Safe b/c value is initialized.
+                Some(unsafe { self.get_unchecked() })
+            } else {
+                None
+            }
+        }
+
+        /// Gets the reference to the underlying value, blocking the current
+        /// thread until it is set.
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let mut cell = std::sync::Arc::new(OnceCell::new());
+        /// let t = std::thread::spawn({
+        ///     let cell = std::sync::Arc::clone(&cell);
+        ///     move || cell.set(92).unwrap()
+        /// });
+        ///
+        /// // Returns immediately, but might return None.
+        /// let _value_or_none = cell.get();
+        ///
+        /// // Will return 92, but might block until the other thread does `.set`.
+        /// let value: &u32 = cell.wait();
+        /// assert_eq!(*value, 92);
+        /// t.join().unwrap();
+        /// ```
+        #[cfg(feature = "std")]
+        pub fn wait(&self) -> &T {
+            if !self.0.is_initialized() {
+                self.0.wait()
+            }
+            debug_assert!(self.0.is_initialized());
+            // Safe b/c of the wait call above and the fact that we didn't
+            // relinquish our borrow.
+            unsafe { self.get_unchecked() }
+        }
+
+        /// Gets the mutable reference to the underlying value.
+        ///
+        /// Returns `None` if the cell is empty.
+        ///
+        /// This method is allowed to violate the invariant of writing to a `OnceCell`
+        /// at most once because it requires `&mut` access to `self`. As with all
+        /// interior mutability, `&mut` access permits arbitrary modification:
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<u32> = OnceCell::new();
+        /// cell.set(92).unwrap();
+        /// cell = OnceCell::new();
+        /// ```
+        #[inline]
+        pub fn get_mut(&mut self) -> Option<&mut T> {
+            self.0.get_mut()
+        }
+
+        /// Get the reference to the underlying value, without checking if the
+        /// cell is initialized.
+        ///
+        /// # Safety
+        ///
+        /// Caller must ensure that the cell is in initialized state, and that
+        /// the contents are acquired by (synchronized to) this thread.
+        #[inline]
+        pub unsafe fn get_unchecked(&self) -> &T {
+            self.0.get_unchecked()
+        }
+
+        /// Sets the contents of this cell to `value`.
+        ///
+        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
+        /// full.
+        ///
+        /// # Example
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// static CELL: OnceCell<i32> = OnceCell::new();
+        ///
+        /// fn main() {
+        ///     assert!(CELL.get().is_none());
+        ///
+        ///     std::thread::spawn(|| {
+        ///         assert_eq!(CELL.set(92), Ok(()));
+        ///     }).join().unwrap();
+        ///
+        ///     assert_eq!(CELL.set(62), Err(62));
+        ///     assert_eq!(CELL.get(), Some(&92));
+        /// }
+        /// ```
+        pub fn set(&self, value: T) -> Result<(), T> {
+            match self.try_insert(value) {
+                Ok(_) => Ok(()),
+                Err((_, value)) => Err(value),
+            }
+        }
+
+        /// Like [`set`](Self::set), but also returns a reference to the final cell value.
+        ///
+        /// # Example
+        ///
+        /// ```
+        /// use once_cell::unsync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// assert!(cell.get().is_none());
+        ///
+        /// assert_eq!(cell.try_insert(92), Ok(&92));
+        /// assert_eq!(cell.try_insert(62), Err((&92, 62)));
+        ///
+        /// assert!(cell.get().is_some());
+        /// ```
+        pub fn try_insert(&self, value: T) -> Result<&T, (&T, T)> {
+            let mut value = Some(value);
+            let res = self.get_or_init(|| unsafe { value.take().unwrap_unchecked() });
+            match value {
+                None => Ok(res),
+                Some(value) => Err((res, value)),
+            }
+        }
+
+        /// Gets the contents of the cell, initializing it with `f` if the cell
+        /// was empty.
+        ///
+        /// Many threads may call `get_or_init` concurrently with different
+        /// initializing functions, but it is guaranteed that only one function
+        /// will be executed.
+        ///
+        /// # Panics
+        ///
+        /// If `f` panics, the panic is propagated to the caller, and the cell
+        /// remains uninitialized.
+        ///
+        /// It is an error to reentrantly initialize the cell from `f`. The
+        /// exact outcome is unspecified. Current implementation deadlocks, but
+        /// this may be changed to a panic in the future.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// let value = cell.get_or_init(|| 92);
+        /// assert_eq!(value, &92);
+        /// let value = cell.get_or_init(|| unreachable!());
+        /// assert_eq!(value, &92);
+        /// ```
+        pub fn get_or_init<F>(&self, f: F) -> &T
+        where
+            F: FnOnce() -> T,
+        {
+            enum Void {}
+            match self.get_or_try_init(|| Ok::<T, Void>(f())) {
+                Ok(val) => val,
+                Err(void) => match void {},
+            }
+        }
+
+        /// Gets the contents of the cell, initializing it with `f` if
+        /// the cell was empty. If the cell was empty and `f` failed, an
+        /// error is returned.
+        ///
+        /// # Panics
+        ///
+        /// If `f` panics, the panic is propagated to the caller, and
+        /// the cell remains uninitialized.
+        ///
+        /// It is an error to reentrantly initialize the cell from `f`.
+        /// The exact outcome is unspecified. Current implementation
+        /// deadlocks, but this may be changed to a panic in the future.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let cell = OnceCell::new();
+        /// assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
+        /// assert!(cell.get().is_none());
+        /// let value = cell.get_or_try_init(|| -> Result<i32, ()> {
+        ///     Ok(92)
+        /// });
+        /// assert_eq!(value, Ok(&92));
+        /// assert_eq!(cell.get(), Some(&92))
+        /// ```
+        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
+        where
+            F: FnOnce() -> Result<T, E>,
+        {
+            // Fast path check
+            if let Some(value) = self.get() {
+                return Ok(value);
+            }
+
+            self.0.initialize(f)?;
+
+            // Safe b/c value is initialized.
+            debug_assert!(self.0.is_initialized());
+            Ok(unsafe { self.get_unchecked() })
+        }
+
+        /// Takes the value out of this `OnceCell`, moving it back to an uninitialized state.
+        ///
+        /// Has no effect and returns `None` if the `OnceCell` hasn't been initialized.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<String> = OnceCell::new();
+        /// assert_eq!(cell.take(), None);
+        ///
+        /// let mut cell = OnceCell::new();
+        /// cell.set("hello".to_string()).unwrap();
+        /// assert_eq!(cell.take(), Some("hello".to_string()));
+        /// assert_eq!(cell.get(), None);
+        /// ```
+        ///
+        /// This method is allowed to violate the invariant of writing to a `OnceCell`
+        /// at most once because it requires `&mut` access to `self`. As with all
+        /// interior mutability, `&mut` access permits arbitrary modification:
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let mut cell: OnceCell<u32> = OnceCell::new();
+        /// cell.set(92).unwrap();
+        /// cell = OnceCell::new();
+        /// ```
+        pub fn take(&mut self) -> Option<T> {
+            mem::take(self).into_inner()
+        }
+
+        /// Consumes the `OnceCell`, returning the wrapped value. Returns
+        /// `None` if the cell was empty.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// use once_cell::sync::OnceCell;
+        ///
+        /// let cell: OnceCell<String> = OnceCell::new();
+        /// assert_eq!(cell.into_inner(), None);
+        ///
+        /// let cell = OnceCell::new();
+        /// cell.set("hello".to_string()).unwrap();
+        /// assert_eq!(cell.into_inner(), Some("hello".to_string()));
+        /// ```
+        #[inline]
+        pub fn into_inner(self) -> Option<T> {
+            self.0.into_inner()
+        }
+    }
+
+    /// A value which is initialized on the first access.
+    ///
+    /// This type is thread-safe and can be used in statics.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use std::collections::HashMap;
+    ///
+    /// use once_cell::sync::Lazy;
+    ///
+    /// static HASHMAP: Lazy<HashMap<i32, String>> = Lazy::new(|| {
+    ///     println!("initializing");
+    ///     let mut m = HashMap::new();
+    ///     m.insert(13, "Spica".to_string());
+    ///     m.insert(74, "Hoyten".to_string());
+    ///     m
+    /// });
+    ///
+    /// fn main() {
+    ///     println!("ready");
+    ///     std::thread::spawn(|| {
+    ///         println!("{:?}", HASHMAP.get(&13));
+    ///     }).join().unwrap();
+    ///     println!("{:?}", HASHMAP.get(&74));
+    ///
+    ///     // Prints:
+    ///     //   ready
+    ///     //   initializing
+    ///     //   Some("Spica")
+    ///     //   Some("Hoyten")
+    /// }
+    /// ```
+    pub struct Lazy<T, F = fn() -> T> {
+        cell: OnceCell<T>,
+        init: Cell<Option<F>>,
+    }
+
+    impl<T: fmt::Debug, F> fmt::Debug for Lazy<T, F> {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            f.debug_struct("Lazy").field("cell", &self.cell).field("init", &"..").finish()
+        }
+    }
+
+    // We never create a `&F` from a `&Lazy<T, F>` so it is fine to not impl
+    // `Sync` for `F`. We do create a `&mut Option<F>` in `force`, but this is
+    // properly synchronized, so it only happens once so it also does not
+    // contribute to this impl.
+    unsafe impl<T, F: Send> Sync for Lazy<T, F> where OnceCell<T>: Sync {}
+    // auto-derived `Send` impl is OK.
+
+    impl<T, F: RefUnwindSafe> RefUnwindSafe for Lazy<T, F> where OnceCell<T>: RefUnwindSafe {}
+
+    impl<T, F> Lazy<T, F> {
+        /// Creates a new lazy value with the given initializing
+        /// function.
+        pub const fn new(f: F) -> Lazy<T, F> {
+            Lazy { cell: OnceCell::new(), init: Cell::new(Some(f)) }
+        }
+
+        /// Consumes this `Lazy` returning the stored value.
+        ///
+        /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
+        pub fn into_value(this: Lazy<T, F>) -> Result<T, F> {
+            let cell = this.cell;
+            let init = this.init;
+            cell.into_inner().ok_or_else(|| {
+                init.take().unwrap_or_else(|| panic!("Lazy instance has previously been poisoned"))
+            })
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> Lazy<T, F> {
+        /// Forces the evaluation of this lazy value and
+        /// returns a reference to the result. This is equivalent
+        /// to the `Deref` impl, but is explicit.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::Lazy;
+        ///
+        /// let lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::force(&lazy), &92);
+        /// assert_eq!(&*lazy, &92);
+        /// ```
+        pub fn force(this: &Lazy<T, F>) -> &T {
+            this.cell.get_or_init(|| match this.init.take() {
+                Some(f) => f(),
+                None => panic!("Lazy instance has previously been poisoned"),
+            })
+        }
+
+        /// Forces the evaluation of this lazy value and
+        /// returns a mutable reference to the result. This is equivalent
+        /// to the `Deref` impl, but is explicit.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::Lazy;
+        ///
+        /// let mut lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::force_mut(&mut lazy), &mut 92);
+        /// ```
+        pub fn force_mut(this: &mut Lazy<T, F>) -> &mut T {
+            if this.cell.get_mut().is_none() {
+                let value = match this.init.get_mut().take() {
+                    Some(f) => f(),
+                    None => panic!("Lazy instance has previously been poisoned"),
+                };
+                this.cell = OnceCell::with_value(value);
+            }
+            this.cell.get_mut().unwrap_or_else(|| unreachable!())
+        }
+
+        /// Gets the reference to the result of this lazy value if
+        /// it was initialized, otherwise returns `None`.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::Lazy;
+        ///
+        /// let lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::get(&lazy), None);
+        /// assert_eq!(&*lazy, &92);
+        /// assert_eq!(Lazy::get(&lazy), Some(&92));
+        /// ```
+        pub fn get(this: &Lazy<T, F>) -> Option<&T> {
+            this.cell.get()
+        }
+
+        /// Gets the reference to the result of this lazy value if
+        /// it was initialized, otherwise returns `None`.
+        ///
+        /// # Example
+        /// ```
+        /// use once_cell::sync::Lazy;
+        ///
+        /// let mut lazy = Lazy::new(|| 92);
+        ///
+        /// assert_eq!(Lazy::get_mut(&mut lazy), None);
+        /// assert_eq!(&*lazy, &92);
+        /// assert_eq!(Lazy::get_mut(&mut lazy), Some(&mut 92));
+        /// ```
+        pub fn get_mut(this: &mut Lazy<T, F>) -> Option<&mut T> {
+            this.cell.get_mut()
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
+        type Target = T;
+        fn deref(&self) -> &T {
+            Lazy::force(self)
+        }
+    }
+
+    impl<T, F: FnOnce() -> T> DerefMut for Lazy<T, F> {
+        fn deref_mut(&mut self) -> &mut T {
+            Lazy::force_mut(self)
+        }
+    }
+
+    impl<T: Default> Default for Lazy<T> {
+        /// Creates a new lazy value using `Default` as the initializing function.
+        fn default() -> Lazy<T> {
+            Lazy::new(T::default)
+        }
+    }
+
+    /// ```compile_fail
+    /// struct S(*mut ());
+    /// unsafe impl Sync for S {}
+    ///
+    /// fn share<T: Sync>(_: &T) {}
+    /// share(&once_cell::sync::OnceCell::<S>::new());
+    /// ```
+    ///
+    /// ```compile_fail
+    /// struct S(*mut ());
+    /// unsafe impl Sync for S {}
+    ///
+    /// fn share<T: Sync>(_: &T) {}
+    /// share(&once_cell::sync::Lazy::<S>::new(|| unimplemented!()));
+    /// ```
+    fn _dummy() {}
+}
+
+#[cfg(feature = "race")]
+pub mod race;
diff --git a/vendor/once_cell/src/race.rs b/vendor/once_cell/src/race.rs
new file mode 100644
index 0000000..fe36fa1
--- /dev/null
+++ b/vendor/once_cell/src/race.rs
@@ -0,0 +1,419 @@
+//! Thread-safe, non-blocking, "first one wins" flavor of `OnceCell`.
+//!
+//! If two threads race to initialize a type from the `race` module, they
+//! don't block, execute initialization function together, but only one of
+//! them stores the result.
+//!
+//! This module does not require `std` feature.
+//!
+//! # Atomic orderings
+//!
+//! All types in this module use `Acquire` and `Release`
+//! [atomic orderings](Ordering) for all their operations. While this is not
+//! strictly necessary for types other than `OnceBox`, it is useful for users as
+//! it allows them to be certain that after `get` or `get_or_init` returns on
+//! one thread, any side-effects caused by the setter thread prior to them
+//! calling `set` or `get_or_init` will be made visible to that thread; without
+//! it, it's possible for it to appear as if they haven't happened yet from the
+//! getter thread's perspective. This is an acceptable tradeoff to make since
+//! `Acquire` and `Release` have very little performance overhead on most
+//! architectures versus `Relaxed`.
+
+#[cfg(feature = "critical-section")]
+use atomic_polyfill as atomic;
+#[cfg(not(feature = "critical-section"))]
+use core::sync::atomic;
+
+use atomic::{AtomicPtr, AtomicUsize, Ordering};
+use core::cell::UnsafeCell;
+use core::marker::PhantomData;
+use core::num::NonZeroUsize;
+use core::ptr;
+
+/// A thread-safe cell which can be written to only once.
+#[derive(Default, Debug)]
+pub struct OnceNonZeroUsize {
+    inner: AtomicUsize,
+}
+
+impl OnceNonZeroUsize {
+    /// Creates a new empty cell.
+    #[inline]
+    pub const fn new() -> OnceNonZeroUsize {
+        OnceNonZeroUsize { inner: AtomicUsize::new(0) }
+    }
+
+    /// Gets the underlying value.
+    #[inline]
+    pub fn get(&self) -> Option<NonZeroUsize> {
+        let val = self.inner.load(Ordering::Acquire);
+        NonZeroUsize::new(val)
+    }
+
+    /// Sets the contents of this cell to `value`.
+    ///
+    /// Returns `Ok(())` if the cell was empty and `Err(())` if it was
+    /// full.
+    #[inline]
+    pub fn set(&self, value: NonZeroUsize) -> Result<(), ()> {
+        let exchange =
+            self.inner.compare_exchange(0, value.get(), Ordering::AcqRel, Ordering::Acquire);
+        match exchange {
+            Ok(_) => Ok(()),
+            Err(_) => Err(()),
+        }
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if the cell was
+    /// empty.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_init<F>(&self, f: F) -> NonZeroUsize
+    where
+        F: FnOnce() -> NonZeroUsize,
+    {
+        enum Void {}
+        match self.get_or_try_init(|| Ok::<NonZeroUsize, Void>(f())) {
+            Ok(val) => val,
+            Err(void) => match void {},
+        }
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if
+    /// the cell was empty. If the cell was empty and `f` failed, an
+    /// error is returned.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<NonZeroUsize, E>
+    where
+        F: FnOnce() -> Result<NonZeroUsize, E>,
+    {
+        let val = self.inner.load(Ordering::Acquire);
+        let res = match NonZeroUsize::new(val) {
+            Some(it) => it,
+            None => {
+                let mut val = f()?.get();
+                let exchange =
+                    self.inner.compare_exchange(0, val, Ordering::AcqRel, Ordering::Acquire);
+                if let Err(old) = exchange {
+                    val = old;
+                }
+                unsafe { NonZeroUsize::new_unchecked(val) }
+            }
+        };
+        Ok(res)
+    }
+}
+
+/// A thread-safe cell which can be written to only once.
+#[derive(Default, Debug)]
+pub struct OnceBool {
+    inner: OnceNonZeroUsize,
+}
+
+impl OnceBool {
+    /// Creates a new empty cell.
+    #[inline]
+    pub const fn new() -> OnceBool {
+        OnceBool { inner: OnceNonZeroUsize::new() }
+    }
+
+    /// Gets the underlying value.
+    #[inline]
+    pub fn get(&self) -> Option<bool> {
+        self.inner.get().map(OnceBool::from_usize)
+    }
+
+    /// Sets the contents of this cell to `value`.
+    ///
+    /// Returns `Ok(())` if the cell was empty and `Err(())` if it was
+    /// full.
+    #[inline]
+    pub fn set(&self, value: bool) -> Result<(), ()> {
+        self.inner.set(OnceBool::to_usize(value))
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if the cell was
+    /// empty.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_init<F>(&self, f: F) -> bool
+    where
+        F: FnOnce() -> bool,
+    {
+        OnceBool::from_usize(self.inner.get_or_init(|| OnceBool::to_usize(f())))
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if
+    /// the cell was empty. If the cell was empty and `f` failed, an
+    /// error is returned.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<bool, E>
+    where
+        F: FnOnce() -> Result<bool, E>,
+    {
+        self.inner.get_or_try_init(|| f().map(OnceBool::to_usize)).map(OnceBool::from_usize)
+    }
+
+    #[inline]
+    fn from_usize(value: NonZeroUsize) -> bool {
+        value.get() == 1
+    }
+
+    #[inline]
+    fn to_usize(value: bool) -> NonZeroUsize {
+        unsafe { NonZeroUsize::new_unchecked(if value { 1 } else { 2 }) }
+    }
+}
+
+/// A thread-safe cell which can be written to only once.
+pub struct OnceRef<'a, T> {
+    inner: AtomicPtr<T>,
+    ghost: PhantomData<UnsafeCell<&'a T>>,
+}
+
+// TODO: Replace UnsafeCell with SyncUnsafeCell once stabilized
+unsafe impl<'a, T: Sync> Sync for OnceRef<'a, T> {}
+
+impl<'a, T> core::fmt::Debug for OnceRef<'a, T> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "OnceRef({:?})", self.inner)
+    }
+}
+
+impl<'a, T> Default for OnceRef<'a, T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<'a, T> OnceRef<'a, T> {
+    /// Creates a new empty cell.
+    pub const fn new() -> OnceRef<'a, T> {
+        OnceRef { inner: AtomicPtr::new(ptr::null_mut()), ghost: PhantomData }
+    }
+
+    /// Gets a reference to the underlying value.
+    pub fn get(&self) -> Option<&'a T> {
+        let ptr = self.inner.load(Ordering::Acquire);
+        unsafe { ptr.as_ref() }
+    }
+
+    /// Sets the contents of this cell to `value`.
+    ///
+    /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
+    /// full.
+    pub fn set(&self, value: &'a T) -> Result<(), ()> {
+        let ptr = value as *const T as *mut T;
+        let exchange =
+            self.inner.compare_exchange(ptr::null_mut(), ptr, Ordering::AcqRel, Ordering::Acquire);
+        match exchange {
+            Ok(_) => Ok(()),
+            Err(_) => Err(()),
+        }
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if the cell was
+    /// empty.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_init<F>(&self, f: F) -> &'a T
+    where
+        F: FnOnce() -> &'a T,
+    {
+        enum Void {}
+        match self.get_or_try_init(|| Ok::<&'a T, Void>(f())) {
+            Ok(val) => val,
+            Err(void) => match void {},
+        }
+    }
+
+    /// Gets the contents of the cell, initializing it with `f` if
+    /// the cell was empty. If the cell was empty and `f` failed, an
+    /// error is returned.
+    ///
+    /// If several threads concurrently run `get_or_init`, more than one `f` can
+    /// be called. However, all threads will return the same value, produced by
+    /// some `f`.
+    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&'a T, E>
+    where
+        F: FnOnce() -> Result<&'a T, E>,
+    {
+        let mut ptr = self.inner.load(Ordering::Acquire);
+
+        if ptr.is_null() {
+            // TODO replace with `cast_mut` when MSRV reaches 1.65.0 (also in `set`)
+            ptr = f()? as *const T as *mut T;
+            let exchange = self.inner.compare_exchange(
+                ptr::null_mut(),
+                ptr,
+                Ordering::AcqRel,
+                Ordering::Acquire,
+            );
+            if let Err(old) = exchange {
+                ptr = old;
+            }
+        }
+
+        Ok(unsafe { &*ptr })
+    }
+
+    /// ```compile_fail
+    /// use once_cell::race::OnceRef;
+    ///
+    /// let mut l = OnceRef::new();
+    ///
+    /// {
+    ///     let y = 2;
+    ///     let mut r = OnceRef::new();
+    ///     r.set(&y).unwrap();
+    ///     core::mem::swap(&mut l, &mut r);
+    /// }
+    ///
+    /// // l now contains a dangling reference to y
+    /// eprintln!("uaf: {}", l.get().unwrap());
+    /// ```
+    fn _dummy() {}
+}
+
+#[cfg(feature = "alloc")]
+pub use self::once_box::OnceBox;
+
+#[cfg(feature = "alloc")]
+mod once_box {
+    use super::atomic::{AtomicPtr, Ordering};
+    use core::{marker::PhantomData, ptr};
+
+    use alloc::boxed::Box;
+
+    /// A thread-safe cell which can be written to only once.
+    pub struct OnceBox<T> {
+        inner: AtomicPtr<T>,
+        ghost: PhantomData<Option<Box<T>>>,
+    }
+
+    impl<T> core::fmt::Debug for OnceBox<T> {
+        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+            write!(f, "OnceBox({:?})", self.inner.load(Ordering::Relaxed))
+        }
+    }
+
+    impl<T> Default for OnceBox<T> {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+
+    impl<T> Drop for OnceBox<T> {
+        fn drop(&mut self) {
+            let ptr = *self.inner.get_mut();
+            if !ptr.is_null() {
+                drop(unsafe { Box::from_raw(ptr) })
+            }
+        }
+    }
+
+    impl<T> OnceBox<T> {
+        /// Creates a new empty cell.
+        pub const fn new() -> OnceBox<T> {
+            OnceBox { inner: AtomicPtr::new(ptr::null_mut()), ghost: PhantomData }
+        }
+
+        /// Gets a reference to the underlying value.
+        pub fn get(&self) -> Option<&T> {
+            let ptr = self.inner.load(Ordering::Acquire);
+            if ptr.is_null() {
+                return None;
+            }
+            Some(unsafe { &*ptr })
+        }
+
+        /// Sets the contents of this cell to `value`.
+        ///
+        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
+        /// full.
+        pub fn set(&self, value: Box<T>) -> Result<(), Box<T>> {
+            let ptr = Box::into_raw(value);
+            let exchange = self.inner.compare_exchange(
+                ptr::null_mut(),
+                ptr,
+                Ordering::AcqRel,
+                Ordering::Acquire,
+            );
+            if exchange.is_err() {
+                let value = unsafe { Box::from_raw(ptr) };
+                return Err(value);
+            }
+            Ok(())
+        }
+
+        /// Gets the contents of the cell, initializing it with `f` if the cell was
+        /// empty.
+        ///
+        /// If several threads concurrently run `get_or_init`, more than one `f` can
+        /// be called. However, all threads will return the same value, produced by
+        /// some `f`.
+        pub fn get_or_init<F>(&self, f: F) -> &T
+        where
+            F: FnOnce() -> Box<T>,
+        {
+            enum Void {}
+            match self.get_or_try_init(|| Ok::<Box<T>, Void>(f())) {
+                Ok(val) => val,
+                Err(void) => match void {},
+            }
+        }
+
+        /// Gets the contents of the cell, initializing it with `f` if
+        /// the cell was empty. If the cell was empty and `f` failed, an
+        /// error is returned.
+        ///
+        /// If several threads concurrently run `get_or_init`, more than one `f` can
+        /// be called. However, all threads will return the same value, produced by
+        /// some `f`.
+        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
+        where
+            F: FnOnce() -> Result<Box<T>, E>,
+        {
+            let mut ptr = self.inner.load(Ordering::Acquire);
+
+            if ptr.is_null() {
+                let val = f()?;
+                ptr = Box::into_raw(val);
+                let exchange = self.inner.compare_exchange(
+                    ptr::null_mut(),
+                    ptr,
+                    Ordering::AcqRel,
+                    Ordering::Acquire,
+                );
+                if let Err(old) = exchange {
+                    drop(unsafe { Box::from_raw(ptr) });
+                    ptr = old;
+                }
+            };
+            Ok(unsafe { &*ptr })
+        }
+    }
+
+    unsafe impl<T: Sync + Send> Sync for OnceBox<T> {}
+
+    /// ```compile_fail
+    /// struct S(*mut ());
+    /// unsafe impl Sync for S {}
+    ///
+    /// fn share<T: Sync>(_: &T) {}
+    /// share(&once_cell::race::OnceBox::<S>::new());
+    /// ```
+    fn _dummy() {}
+}
diff --git a/vendor/once_cell/tests/it/main.rs b/vendor/once_cell/tests/it/main.rs
new file mode 100644
index 0000000..b8e56cc
--- /dev/null
+++ b/vendor/once_cell/tests/it/main.rs
@@ -0,0 +1,12 @@
+mod unsync_once_cell;
+#[cfg(any(feature = "std", feature = "critical-section"))]
+mod sync_once_cell;
+
+mod unsync_lazy;
+#[cfg(any(feature = "std", feature = "critical-section"))]
+mod sync_lazy;
+
+#[cfg(feature = "race")]
+mod race;
+#[cfg(all(feature = "race", feature = "alloc"))]
+mod race_once_box;
diff --git a/vendor/once_cell/tests/it/race.rs b/vendor/once_cell/tests/it/race.rs
new file mode 100644
index 0000000..24884dd
--- /dev/null
+++ b/vendor/once_cell/tests/it/race.rs
@@ -0,0 +1,128 @@
+#[cfg(feature = "std")]
+use std::sync::Barrier;
+use std::{
+    num::NonZeroUsize,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+    thread::scope,
+};
+
+use once_cell::race::{OnceBool, OnceNonZeroUsize};
+
+#[test]
+fn once_non_zero_usize_smoke_test() {
+    let cnt = AtomicUsize::new(0);
+    let cell = OnceNonZeroUsize::new();
+    let val = NonZeroUsize::new(92).unwrap();
+    scope(|s| {
+        s.spawn(|| {
+            assert_eq!(
+                cell.get_or_init(|| {
+                    cnt.fetch_add(1, SeqCst);
+                    val
+                }),
+                val
+            );
+            assert_eq!(cnt.load(SeqCst), 1);
+
+            assert_eq!(
+                cell.get_or_init(|| {
+                    cnt.fetch_add(1, SeqCst);
+                    val
+                }),
+                val
+            );
+            assert_eq!(cnt.load(SeqCst), 1);
+        });
+    });
+    assert_eq!(cell.get(), Some(val));
+    assert_eq!(cnt.load(SeqCst), 1);
+}
+
+#[test]
+fn once_non_zero_usize_set() {
+    let val1 = NonZeroUsize::new(92).unwrap();
+    let val2 = NonZeroUsize::new(62).unwrap();
+
+    let cell = OnceNonZeroUsize::new();
+
+    assert!(cell.set(val1).is_ok());
+    assert_eq!(cell.get(), Some(val1));
+
+    assert!(cell.set(val2).is_err());
+    assert_eq!(cell.get(), Some(val1));
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn once_non_zero_usize_first_wins() {
+    let val1 = NonZeroUsize::new(92).unwrap();
+    let val2 = NonZeroUsize::new(62).unwrap();
+
+    let cell = OnceNonZeroUsize::new();
+
+    let b1 = Barrier::new(2);
+    let b2 = Barrier::new(2);
+    let b3 = Barrier::new(2);
+    scope(|s| {
+        s.spawn(|| {
+            let r1 = cell.get_or_init(|| {
+                b1.wait();
+                b2.wait();
+                val1
+            });
+            assert_eq!(r1, val1);
+            b3.wait();
+        });
+        b1.wait();
+        s.spawn(|| {
+            let r2 = cell.get_or_init(|| {
+                b2.wait();
+                b3.wait();
+                val2
+            });
+            assert_eq!(r2, val1);
+        });
+    });
+
+    assert_eq!(cell.get(), Some(val1));
+}
+
+#[test]
+fn once_bool_smoke_test() {
+    let cnt = AtomicUsize::new(0);
+    let cell = OnceBool::new();
+    scope(|s| {
+        s.spawn(|| {
+            assert_eq!(
+                cell.get_or_init(|| {
+                    cnt.fetch_add(1, SeqCst);
+                    false
+                }),
+                false
+            );
+            assert_eq!(cnt.load(SeqCst), 1);
+
+            assert_eq!(
+                cell.get_or_init(|| {
+                    cnt.fetch_add(1, SeqCst);
+                    false
+                }),
+                false
+            );
+            assert_eq!(cnt.load(SeqCst), 1);
+        });
+    });
+    assert_eq!(cell.get(), Some(false));
+    assert_eq!(cnt.load(SeqCst), 1);
+}
+
+#[test]
+fn once_bool_set() {
+    let cell = OnceBool::new();
+
+    assert!(cell.set(false).is_ok());
+    assert_eq!(cell.get(), Some(false));
+
+    assert!(cell.set(true).is_err());
+    assert_eq!(cell.get(), Some(false));
+}
diff --git a/vendor/once_cell/tests/it/race_once_box.rs b/vendor/once_cell/tests/it/race_once_box.rs
new file mode 100644
index 0000000..0bf3852
--- /dev/null
+++ b/vendor/once_cell/tests/it/race_once_box.rs
@@ -0,0 +1,145 @@
+#[cfg(feature = "std")]
+use std::sync::Barrier;
+use std::sync::{
+    atomic::{AtomicUsize, Ordering::SeqCst},
+    Arc,
+};
+
+use once_cell::race::OnceBox;
+
+#[derive(Default)]
+struct Heap {
+    total: Arc<AtomicUsize>,
+}
+
+#[derive(Debug)]
+struct Pebble<T> {
+    val: T,
+    total: Arc<AtomicUsize>,
+}
+
+impl<T> Drop for Pebble<T> {
+    fn drop(&mut self) {
+        self.total.fetch_sub(1, SeqCst);
+    }
+}
+
+impl Heap {
+    fn total(&self) -> usize {
+        self.total.load(SeqCst)
+    }
+    fn new_pebble<T>(&self, val: T) -> Pebble<T> {
+        self.total.fetch_add(1, SeqCst);
+        Pebble { val, total: Arc::clone(&self.total) }
+    }
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn once_box_smoke_test() {
+    use std::thread::scope;
+
+    let heap = Heap::default();
+    let global_cnt = AtomicUsize::new(0);
+    let cell = OnceBox::new();
+    let b = Barrier::new(128);
+    scope(|s| {
+        for _ in 0..128 {
+            s.spawn(|| {
+                let local_cnt = AtomicUsize::new(0);
+                cell.get_or_init(|| {
+                    global_cnt.fetch_add(1, SeqCst);
+                    local_cnt.fetch_add(1, SeqCst);
+                    b.wait();
+                    Box::new(heap.new_pebble(()))
+                });
+                assert_eq!(local_cnt.load(SeqCst), 1);
+
+                cell.get_or_init(|| {
+                    global_cnt.fetch_add(1, SeqCst);
+                    local_cnt.fetch_add(1, SeqCst);
+                    Box::new(heap.new_pebble(()))
+                });
+                assert_eq!(local_cnt.load(SeqCst), 1);
+            });
+        }
+    });
+    assert!(cell.get().is_some());
+    assert!(global_cnt.load(SeqCst) > 10);
+
+    assert_eq!(heap.total(), 1);
+    drop(cell);
+    assert_eq!(heap.total(), 0);
+}
+
+#[test]
+fn once_box_set() {
+    let heap = Heap::default();
+    let cell = OnceBox::new();
+    assert!(cell.get().is_none());
+
+    assert!(cell.set(Box::new(heap.new_pebble("hello"))).is_ok());
+    assert_eq!(cell.get().unwrap().val, "hello");
+    assert_eq!(heap.total(), 1);
+
+    assert!(cell.set(Box::new(heap.new_pebble("world"))).is_err());
+    assert_eq!(cell.get().unwrap().val, "hello");
+    assert_eq!(heap.total(), 1);
+
+    drop(cell);
+    assert_eq!(heap.total(), 0);
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn once_box_first_wins() {
+    use std::thread::scope;
+
+    let cell = OnceBox::new();
+    let val1 = 92;
+    let val2 = 62;
+
+    let b1 = Barrier::new(2);
+    let b2 = Barrier::new(2);
+    let b3 = Barrier::new(2);
+    scope(|s| {
+        s.spawn(|| {
+            let r1 = cell.get_or_init(|| {
+                b1.wait();
+                b2.wait();
+                Box::new(val1)
+            });
+            assert_eq!(*r1, val1);
+            b3.wait();
+        });
+        b1.wait();
+        s.spawn(|| {
+            let r2 = cell.get_or_init(|| {
+                b2.wait();
+                b3.wait();
+                Box::new(val2)
+            });
+            assert_eq!(*r2, val1);
+        });
+    });
+
+    assert_eq!(cell.get(), Some(&val1));
+}
+
+#[test]
+fn once_box_reentrant() {
+    let cell = OnceBox::new();
+    let res = cell.get_or_init(|| {
+        cell.get_or_init(|| Box::new("hello".to_string()));
+        Box::new("world".to_string())
+    });
+    assert_eq!(res, "hello");
+}
+
+#[test]
+fn once_box_default() {
+    struct Foo;
+
+    let cell: OnceBox<Foo> = Default::default();
+    assert!(cell.get().is_none());
+}
diff --git a/vendor/once_cell/tests/it/sync_lazy.rs b/vendor/once_cell/tests/it/sync_lazy.rs
new file mode 100644
index 0000000..44d70fa
--- /dev/null
+++ b/vendor/once_cell/tests/it/sync_lazy.rs
@@ -0,0 +1,176 @@
+use std::{
+    cell::Cell,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+    thread::scope,
+};
+
+use once_cell::sync::{Lazy, OnceCell};
+
+#[test]
+fn lazy_new() {
+    let called = AtomicUsize::new(0);
+    let x = Lazy::new(|| {
+        called.fetch_add(1, SeqCst);
+        92
+    });
+
+    assert_eq!(called.load(SeqCst), 0);
+
+    scope(|s| {
+        s.spawn(|| {
+            let y = *x - 30;
+            assert_eq!(y, 62);
+            assert_eq!(called.load(SeqCst), 1);
+        });
+    });
+
+    let y = *x - 30;
+    assert_eq!(y, 62);
+    assert_eq!(called.load(SeqCst), 1);
+}
+
+#[test]
+fn lazy_deref_mut() {
+    let called = AtomicUsize::new(0);
+    let mut x = Lazy::new(|| {
+        called.fetch_add(1, SeqCst);
+        92
+    });
+
+    assert_eq!(called.load(SeqCst), 0);
+
+    let y = *x - 30;
+    assert_eq!(y, 62);
+    assert_eq!(called.load(SeqCst), 1);
+
+    *x /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.load(SeqCst), 1);
+}
+
+#[test]
+fn lazy_force_mut() {
+    let called = Cell::new(0);
+    let mut x = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+    assert_eq!(called.get(), 0);
+    let v = Lazy::force_mut(&mut x);
+    assert_eq!(called.get(), 1);
+
+    *v /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_get_mut() {
+    let called = Cell::new(0);
+    let mut x: Lazy<u32, _> = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+
+    assert_eq!(called.get(), 0);
+    assert_eq!(*x, 92);
+
+    let mut_ref: &mut u32 = Lazy::get_mut(&mut x).unwrap();
+    assert_eq!(called.get(), 1);
+
+    *mut_ref /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_default() {
+    static CALLED: AtomicUsize = AtomicUsize::new(0);
+
+    struct Foo(u8);
+    impl Default for Foo {
+        fn default() -> Self {
+            CALLED.fetch_add(1, SeqCst);
+            Foo(42)
+        }
+    }
+
+    let lazy: Lazy<std::sync::Mutex<Foo>> = <_>::default();
+
+    assert_eq!(CALLED.load(SeqCst), 0);
+
+    assert_eq!(lazy.lock().unwrap().0, 42);
+    assert_eq!(CALLED.load(SeqCst), 1);
+
+    lazy.lock().unwrap().0 = 21;
+
+    assert_eq!(lazy.lock().unwrap().0, 21);
+    assert_eq!(CALLED.load(SeqCst), 1);
+}
+
+#[test]
+fn static_lazy() {
+    static XS: Lazy<Vec<i32>> = Lazy::new(|| {
+        let mut xs = Vec::new();
+        xs.push(1);
+        xs.push(2);
+        xs.push(3);
+        xs
+    });
+    scope(|s| {
+        s.spawn(|| {
+            assert_eq!(&*XS, &vec![1, 2, 3]);
+        });
+    });
+    assert_eq!(&*XS, &vec![1, 2, 3]);
+}
+
+#[test]
+fn static_lazy_via_fn() {
+    fn xs() -> &'static Vec<i32> {
+        static XS: OnceCell<Vec<i32>> = OnceCell::new();
+        XS.get_or_init(|| {
+            let mut xs = Vec::new();
+            xs.push(1);
+            xs.push(2);
+            xs.push(3);
+            xs
+        })
+    }
+    assert_eq!(xs(), &vec![1, 2, 3]);
+}
+
+#[test]
+fn lazy_into_value() {
+    let l: Lazy<i32, _> = Lazy::new(|| panic!());
+    assert!(matches!(Lazy::into_value(l), Err(_)));
+    let l = Lazy::new(|| -> i32 { 92 });
+    Lazy::force(&l);
+    assert!(matches!(Lazy::into_value(l), Ok(92)));
+}
+
+#[test]
+fn lazy_poisoning() {
+    let x: Lazy<String> = Lazy::new(|| panic!("kaboom"));
+    for _ in 0..2 {
+        let res = std::panic::catch_unwind(|| x.len());
+        assert!(res.is_err());
+    }
+}
+
+#[test]
+// https://github.com/rust-lang/rust/issues/34761#issuecomment-256320669
+fn arrrrrrrrrrrrrrrrrrrrrr() {
+    let lazy: Lazy<&String, _>;
+    {
+        let s = String::new();
+        lazy = Lazy::new(|| &s);
+        _ = *lazy;
+    }
+}
+
+#[test]
+fn lazy_is_sync_send() {
+    fn assert_traits<T: Send + Sync>() {}
+    assert_traits::<Lazy<String>>();
+}
diff --git a/vendor/once_cell/tests/it/sync_once_cell.rs b/vendor/once_cell/tests/it/sync_once_cell.rs
new file mode 100644
index 0000000..bedc4c8
--- /dev/null
+++ b/vendor/once_cell/tests/it/sync_once_cell.rs
@@ -0,0 +1,309 @@
+use std::{
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+    thread::scope,
+};
+
+#[cfg(feature = "std")]
+use std::sync::Barrier;
+
+#[cfg(not(feature = "std"))]
+use core::cell::Cell;
+
+use once_cell::sync::{Lazy, OnceCell};
+
+#[test]
+fn once_cell() {
+    let c = OnceCell::new();
+    assert!(c.get().is_none());
+    scope(|s| {
+        s.spawn(|| {
+            c.get_or_init(|| 92);
+            assert_eq!(c.get(), Some(&92));
+        });
+    });
+    c.get_or_init(|| panic!("Kabom!"));
+    assert_eq!(c.get(), Some(&92));
+}
+
+#[test]
+fn once_cell_with_value() {
+    static CELL: OnceCell<i32> = OnceCell::with_value(12);
+    assert_eq!(CELL.get(), Some(&12));
+}
+
+#[test]
+fn once_cell_get_mut() {
+    let mut c = OnceCell::new();
+    assert!(c.get_mut().is_none());
+    c.set(90).unwrap();
+    *c.get_mut().unwrap() += 2;
+    assert_eq!(c.get_mut(), Some(&mut 92));
+}
+
+#[test]
+fn once_cell_get_unchecked() {
+    let c = OnceCell::new();
+    c.set(92).unwrap();
+    unsafe {
+        assert_eq!(c.get_unchecked(), &92);
+    }
+}
+
+#[test]
+fn once_cell_drop() {
+    static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
+    struct Dropper;
+    impl Drop for Dropper {
+        fn drop(&mut self) {
+            DROP_CNT.fetch_add(1, SeqCst);
+        }
+    }
+
+    let x = OnceCell::new();
+    scope(|s| {
+        s.spawn(|| {
+            x.get_or_init(|| Dropper);
+            assert_eq!(DROP_CNT.load(SeqCst), 0);
+            drop(x);
+        });
+    });
+    assert_eq!(DROP_CNT.load(SeqCst), 1);
+}
+
+#[test]
+fn once_cell_drop_empty() {
+    let x = OnceCell::<String>::new();
+    drop(x);
+}
+
+#[test]
+fn clone() {
+    let s = OnceCell::new();
+    let c = s.clone();
+    assert!(c.get().is_none());
+
+    s.set("hello".to_string()).unwrap();
+    let c = s.clone();
+    assert_eq!(c.get().map(String::as_str), Some("hello"));
+}
+
+#[test]
+fn get_or_try_init() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert!(cell.get().is_none());
+
+    let res = std::panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() }));
+    assert!(res.is_err());
+    assert!(cell.get().is_none());
+
+    assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
+
+    assert_eq!(cell.get_or_try_init(|| Ok::<_, ()>("hello".to_string())), Ok(&"hello".to_string()));
+    assert_eq!(cell.get(), Some(&"hello".to_string()));
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn wait() {
+    let cell: OnceCell<String> = OnceCell::new();
+    scope(|s| {
+        s.spawn(|| cell.set("hello".to_string()));
+        let greeting = cell.wait();
+        assert_eq!(greeting, "hello")
+    });
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn get_or_init_stress() {
+    let n_threads = if cfg!(miri) { 30 } else { 1_000 };
+    let n_cells = if cfg!(miri) { 30 } else { 1_000 };
+    let cells: Vec<_> = std::iter::repeat_with(|| (Barrier::new(n_threads), OnceCell::new()))
+        .take(n_cells)
+        .collect();
+    scope(|s| {
+        for t in 0..n_threads {
+            let cells = &cells;
+            s.spawn(move || {
+                for (i, (b, s)) in cells.iter().enumerate() {
+                    b.wait();
+                    let j = if t % 2 == 0 { s.wait() } else { s.get_or_init(|| i) };
+                    assert_eq!(*j, i);
+                }
+            });
+        }
+    });
+}
+
+#[test]
+fn from_impl() {
+    assert_eq!(OnceCell::from("value").get(), Some(&"value"));
+    assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
+}
+
+#[test]
+fn partialeq_impl() {
+    assert!(OnceCell::from("value") == OnceCell::from("value"));
+    assert!(OnceCell::from("foo") != OnceCell::from("bar"));
+
+    assert!(OnceCell::<String>::new() == OnceCell::new());
+    assert!(OnceCell::<String>::new() != OnceCell::from("value".to_owned()));
+}
+
+#[test]
+fn into_inner() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert_eq!(cell.into_inner(), None);
+    let cell = OnceCell::new();
+    cell.set("hello".to_string()).unwrap();
+    assert_eq!(cell.into_inner(), Some("hello".to_string()));
+}
+
+#[test]
+fn debug_impl() {
+    let cell = OnceCell::new();
+    assert_eq!(format!("{:#?}", cell), "OnceCell(Uninit)");
+    cell.set(vec!["hello", "world"]).unwrap();
+    assert_eq!(
+        format!("{:#?}", cell),
+        r#"OnceCell(
+    [
+        "hello",
+        "world",
+    ],
+)"#
+    );
+}
+
+/*#[test]
+#[cfg_attr(miri, ignore)] // miri doesn't support processes
+#[cfg(feature = "std")]
+fn reentrant_init() {
+    let examples_dir = {
+        let mut exe = std::env::current_exe().unwrap();
+        exe.pop();
+        exe.pop();
+        exe.push("examples");
+        exe
+    };
+    let bin = examples_dir
+        .join("reentrant_init_deadlocks")
+        .with_extension(std::env::consts::EXE_EXTENSION);
+    let mut guard = Guard { child: std::process::Command::new(bin).spawn().unwrap() };
+    std::thread::sleep(std::time::Duration::from_secs(2));
+    let status = guard.child.try_wait().unwrap();
+    assert!(status.is_none());
+
+    struct Guard {
+        child: std::process::Child,
+    }
+
+    impl Drop for Guard {
+        fn drop(&mut self) {
+            let _ = self.child.kill();
+        }
+    }
+}*/
+
+#[cfg(not(feature = "std"))]
+#[test]
+#[should_panic(expected = "reentrant init")]
+fn reentrant_init() {
+    let x: OnceCell<Box<i32>> = OnceCell::new();
+    let dangling_ref: Cell<Option<&i32>> = Cell::new(None);
+    x.get_or_init(|| {
+        let r = x.get_or_init(|| Box::new(92));
+        dangling_ref.set(Some(r));
+        Box::new(62)
+    });
+    eprintln!("use after free: {:?}", dangling_ref.get().unwrap());
+}
+
+#[test]
+fn eval_once_macro() {
+    macro_rules! eval_once {
+        (|| -> $ty:ty {
+            $($body:tt)*
+        }) => {{
+            static ONCE_CELL: OnceCell<$ty> = OnceCell::new();
+            fn init() -> $ty {
+                $($body)*
+            }
+            ONCE_CELL.get_or_init(init)
+        }};
+    }
+
+    let fib: &'static Vec<i32> = eval_once! {
+        || -> Vec<i32> {
+            let mut res = vec![1, 1];
+            for i in 0..10 {
+                let next = res[i] + res[i + 1];
+                res.push(next);
+            }
+            res
+        }
+    };
+    assert_eq!(fib[5], 8)
+}
+
+#[test]
+fn once_cell_does_not_leak_partially_constructed_boxes() {
+    let n_tries = if cfg!(miri) { 10 } else { 100 };
+    let n_readers = 10;
+    let n_writers = 3;
+    const MSG: &str = "Hello, World";
+
+    for _ in 0..n_tries {
+        let cell: OnceCell<String> = OnceCell::new();
+        scope(|scope| {
+            for _ in 0..n_readers {
+                scope.spawn(|| loop {
+                    if let Some(msg) = cell.get() {
+                        assert_eq!(msg, MSG);
+                        break;
+                    }
+                });
+            }
+            for _ in 0..n_writers {
+                let _ = scope.spawn(|| cell.set(MSG.to_owned()));
+            }
+        });
+    }
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn get_does_not_block() {
+    let cell = OnceCell::new();
+    let barrier = Barrier::new(2);
+    scope(|scope| {
+        scope.spawn(|| {
+            cell.get_or_init(|| {
+                barrier.wait();
+                barrier.wait();
+                "hello".to_string()
+            });
+        });
+        barrier.wait();
+        assert_eq!(cell.get(), None);
+        barrier.wait();
+    });
+    assert_eq!(cell.get(), Some(&"hello".to_string()));
+}
+
+#[test]
+// https://github.com/rust-lang/rust/issues/34761#issuecomment-256320669
+fn arrrrrrrrrrrrrrrrrrrrrr() {
+    let cell = OnceCell::new();
+    {
+        let s = String::new();
+        cell.set(&s).unwrap();
+    }
+}
+
+#[test]
+fn once_cell_is_sync_send() {
+    fn assert_traits<T: Send + Sync>() {}
+    assert_traits::<OnceCell<String>>();
+    assert_traits::<Lazy<String>>();
+}
diff --git a/vendor/once_cell/tests/it/unsync_lazy.rs b/vendor/once_cell/tests/it/unsync_lazy.rs
new file mode 100644
index 0000000..0c308ca
--- /dev/null
+++ b/vendor/once_cell/tests/it/unsync_lazy.rs
@@ -0,0 +1,134 @@
+use core::{
+    cell::Cell,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+};
+
+use once_cell::unsync::Lazy;
+
+#[test]
+fn lazy_new() {
+    let called = Cell::new(0);
+    let x = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+
+    assert_eq!(called.get(), 0);
+
+    let y = *x - 30;
+    assert_eq!(y, 62);
+    assert_eq!(called.get(), 1);
+
+    let y = *x - 30;
+    assert_eq!(y, 62);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_deref_mut() {
+    let called = Cell::new(0);
+    let mut x = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+
+    assert_eq!(called.get(), 0);
+
+    let y = *x - 30;
+    assert_eq!(y, 62);
+    assert_eq!(called.get(), 1);
+
+    *x /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_force_mut() {
+    let called = Cell::new(0);
+    let mut x = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+    assert_eq!(called.get(), 0);
+    let v = Lazy::force_mut(&mut x);
+    assert_eq!(called.get(), 1);
+
+    *v /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_get_mut() {
+    let called = Cell::new(0);
+    let mut x: Lazy<u32, _> = Lazy::new(|| {
+        called.set(called.get() + 1);
+        92
+    });
+
+    assert_eq!(called.get(), 0);
+    assert_eq!(*x, 92);
+
+    let mut_ref: &mut u32 = Lazy::get_mut(&mut x).unwrap();
+    assert_eq!(called.get(), 1);
+
+    *mut_ref /= 2;
+    assert_eq!(*x, 46);
+    assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn lazy_default() {
+    static CALLED: AtomicUsize = AtomicUsize::new(0);
+
+    struct Foo(u8);
+    impl Default for Foo {
+        fn default() -> Self {
+            CALLED.fetch_add(1, SeqCst);
+            Foo(42)
+        }
+    }
+
+    let lazy: Lazy<std::sync::Mutex<Foo>> = <_>::default();
+
+    assert_eq!(CALLED.load(SeqCst), 0);
+
+    assert_eq!(lazy.lock().unwrap().0, 42);
+    assert_eq!(CALLED.load(SeqCst), 1);
+
+    lazy.lock().unwrap().0 = 21;
+
+    assert_eq!(lazy.lock().unwrap().0, 21);
+    assert_eq!(CALLED.load(SeqCst), 1);
+}
+
+#[test]
+fn lazy_into_value() {
+    let l: Lazy<i32, _> = Lazy::new(|| panic!());
+    assert!(matches!(Lazy::into_value(l), Err(_)));
+    let l = Lazy::new(|| -> i32 { 92 });
+    Lazy::force(&l);
+    assert!(matches!(Lazy::into_value(l), Ok(92)));
+}
+
+#[test]
+#[cfg(feature = "std")]
+fn lazy_poisoning() {
+    let x: Lazy<String> = Lazy::new(|| panic!("kaboom"));
+    for _ in 0..2 {
+        let res = std::panic::catch_unwind(|| x.len());
+        assert!(res.is_err());
+    }
+}
+
+#[test]
+// https://github.com/rust-lang/rust/issues/34761#issuecomment-256320669
+fn arrrrrrrrrrrrrrrrrrrrrr() {
+    let lazy: Lazy<&String, _>;
+    {
+        let s = String::new();
+        lazy = Lazy::new(|| &s);
+        _ = *lazy;
+    }
+}
diff --git a/vendor/once_cell/tests/it/unsync_once_cell.rs b/vendor/once_cell/tests/it/unsync_once_cell.rs
new file mode 100644
index 0000000..124cc3e
--- /dev/null
+++ b/vendor/once_cell/tests/it/unsync_once_cell.rs
@@ -0,0 +1,154 @@
+use core::{
+    cell::Cell,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+};
+
+use once_cell::unsync::OnceCell;
+
+#[test]
+fn once_cell() {
+    let c = OnceCell::new();
+    assert!(c.get().is_none());
+    c.get_or_init(|| 92);
+    assert_eq!(c.get(), Some(&92));
+
+    c.get_or_init(|| panic!("Kabom!"));
+    assert_eq!(c.get(), Some(&92));
+}
+
+#[test]
+fn once_cell_with_value() {
+    const CELL: OnceCell<i32> = OnceCell::with_value(12);
+    let cell = CELL;
+    assert_eq!(cell.get(), Some(&12));
+}
+
+#[test]
+fn once_cell_get_mut() {
+    let mut c = OnceCell::new();
+    assert!(c.get_mut().is_none());
+    c.set(90).unwrap();
+    *c.get_mut().unwrap() += 2;
+    assert_eq!(c.get_mut(), Some(&mut 92));
+}
+
+#[test]
+fn once_cell_drop() {
+    static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
+    struct Dropper;
+    impl Drop for Dropper {
+        fn drop(&mut self) {
+            DROP_CNT.fetch_add(1, SeqCst);
+        }
+    }
+
+    let x = OnceCell::new();
+    x.get_or_init(|| Dropper);
+    assert_eq!(DROP_CNT.load(SeqCst), 0);
+    drop(x);
+    assert_eq!(DROP_CNT.load(SeqCst), 1);
+}
+
+#[test]
+fn once_cell_drop_empty() {
+    let x = OnceCell::<String>::new();
+    drop(x);
+}
+
+#[test]
+fn clone() {
+    let s = OnceCell::new();
+    let c = s.clone();
+    assert!(c.get().is_none());
+
+    s.set("hello".to_string()).unwrap();
+    let c = s.clone();
+    assert_eq!(c.get().map(String::as_str), Some("hello"));
+}
+
+#[test]
+fn get_or_try_init() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert!(cell.get().is_none());
+
+    let res = std::panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() }));
+    assert!(res.is_err());
+    assert!(cell.get().is_none());
+
+    assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
+
+    assert_eq!(cell.get_or_try_init(|| Ok::<_, ()>("hello".to_string())), Ok(&"hello".to_string()));
+    assert_eq!(cell.get(), Some(&"hello".to_string()));
+}
+
+#[test]
+fn from_impl() {
+    assert_eq!(OnceCell::from("value").get(), Some(&"value"));
+    assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
+}
+
+#[test]
+fn partialeq_impl() {
+    assert!(OnceCell::from("value") == OnceCell::from("value"));
+    assert!(OnceCell::from("foo") != OnceCell::from("bar"));
+
+    assert!(OnceCell::<String>::new() == OnceCell::new());
+    assert!(OnceCell::<String>::new() != OnceCell::from("value".to_owned()));
+}
+
+#[test]
+fn into_inner() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert_eq!(cell.into_inner(), None);
+    let cell = OnceCell::new();
+    cell.set("hello".to_string()).unwrap();
+    assert_eq!(cell.into_inner(), Some("hello".to_string()));
+}
+
+#[test]
+fn debug_impl() {
+    let cell = OnceCell::new();
+    assert_eq!(format!("{:#?}", cell), "OnceCell(Uninit)");
+    cell.set(vec!["hello", "world"]).unwrap();
+    assert_eq!(
+        format!("{:#?}", cell),
+        r#"OnceCell(
+    [
+        "hello",
+        "world",
+    ],
+)"#
+    );
+}
+
+#[test]
+#[should_panic(expected = "reentrant init")]
+fn reentrant_init() {
+    let x: OnceCell<Box<i32>> = OnceCell::new();
+    let dangling_ref: Cell<Option<&i32>> = Cell::new(None);
+    x.get_or_init(|| {
+        let r = x.get_or_init(|| Box::new(92));
+        dangling_ref.set(Some(r));
+        Box::new(62)
+    });
+    eprintln!("use after free: {:?}", dangling_ref.get().unwrap());
+}
+
+#[test]
+fn aliasing_in_get() {
+    let x = OnceCell::new();
+    x.set(42).unwrap();
+    let at_x = x.get().unwrap(); // --- (shared) borrow of inner `Option<T>` --+
+    let _ = x.set(27); // <-- temporary (unique) borrow of inner `Option<T>`   |
+    println!("{}", at_x); // <------- up until here ---------------------------+
+}
+
+#[test]
+// https://github.com/rust-lang/rust/issues/34761#issuecomment-256320669
+fn arrrrrrrrrrrrrrrrrrrrrr() {
+    let cell = OnceCell::new();
+    {
+        let s = String::new();
+        cell.set(&s).unwrap();
+    }
+}
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-04 12:47:55 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-04 12:47:55 +0000
commit	2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4 (patch)
tree	033cc839730fda84ff08db877037977be94e5e3a /vendor/once_cell
parent	Initial commit. (diff)
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