1 files changed, 54 insertions, 0 deletions
diff --git a/third_party/rust/tokio-stream/src/pending.rs b/third_party/rust/tokio-stream/src/pending.rs
new file mode 100644
index 0000000000..b50fd33354
--- /dev/null
+++ b/third_party/rust/tokio-stream/src/pending.rs
@@ -0,0 +1,54 @@
+use crate::Stream;
+
+use core::marker::PhantomData;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+/// Stream for the [`pending`](fn@pending) function.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct Pending<T>(PhantomData<T>);
+
+impl<T> Unpin for Pending<T> {}
+unsafe impl<T> Send for Pending<T> {}
+unsafe impl<T> Sync for Pending<T> {}
+
+/// Creates a stream that is never ready
+///
+/// The returned stream is never ready. Attempting to call
+/// [`next()`](crate::StreamExt::next) will never complete. Use
+/// [`stream::empty()`](super::empty()) to obtain a stream that is is
+/// immediately empty but returns no values.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```no_run
+/// use tokio_stream::{self as stream, StreamExt};
+///
+/// #[tokio::main]
+/// async fn main() {
+///     let mut never = stream::pending::<i32>();
+///
+///     // This will never complete
+///     never.next().await;
+///
+///     unreachable!();
+/// }
+/// ```
+pub const fn pending<T>() -> Pending<T> {
+    Pending(PhantomData)
+}
+
+impl<T> Stream for Pending<T> {
+    type Item = T;
+
+    fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<T>> {
+        Poll::Pending
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, None)
+    }
+}