Merging upstream version 1.66.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 902 insertions, 0 deletions

diff --git a/vendor/tracing-subscriber-0.3.3/CHANGELOG.md b/vendor/tracing-subscriber-0.3.3/CHANGELOG.md
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@@ -0,0 +1,902 @@
+# 0.3.3 (Nov 29, 2021)
+
+This release fixes a pair of regressions in `tracing-subscriber`'s `fmt` module.
+
+### Fixed
+
+- **fmt**: Fixed missing event fields with `Compact` formatter ([#1755])
+- **fmt**: Fixed `PrettyFields` formatter (and thus `format::Pretty` event
+  formatter) ignoring the `fmt::Layer`'s ANSI color code configuration ([#1747])
+
+[#1755]: https://github.com/tokio-rs/tracing/pull/1755
+[#1747]: https://github.com/tokio-rs/tracing/pull/1747
+
+# 0.3.2 (Nov 19, 2021)
+
+### Fixed
+
+- **fmt**: Fixed `MakeWriter` filtering not working with `BoxMakeWriter`
+  ([#1694])
+
+### Added
+
+- **fmt**: `Writer::has_ansi_escapes` method to check if an output supports ANSI
+  terminal formatting escape codes ([#1696])
+- **fmt**: Added additional ANSI terminal formatting to field formatters when
+  supported ([#1702])
+- **fmt**: Added `FmtContext::span_scope`, `FmtContext::event_scope`, and
+  `FmtContext::parent_span` methods for accessing the current span and its scope
+  when formatting an event ([#1728])
+- **fmt**: Improved documentation on implementing event formatters ([#1727])
+
+[#1694]: https://github.com/tokio-rs/tracing/pull/1694
+[#1696]: https://github.com/tokio-rs/tracing/pull/1696
+[#1702]: https://github.com/tokio-rs/tracing/pull/1702
+[#1728]: https://github.com/tokio-rs/tracing/pull/1728
+[#1727]: https://github.com/tokio-rs/tracing/pull/1727
+# 0.3.1 (Oct 25, 2021)
+
+This release fixes a few issues related to feature flagging.
+
+### Fixed
+
+- **time**: Compilation error when enabling the "time" feature flag without also
+  enabling the "local-time" feature flag ([#1685])
+- **registry**: Unused method warnings when the "std" feature is enabled but the
+  "registry" feature is disabled ([#1686])
+
+[#1685]: https://github.com/tokio-rs/tracing/pull/1685
+[#1686]: https://github.com/tokio-rs/tracing/pull/1686
+
+# 0.3.0 (Oct 22, 2021)
+
+This is a breaking release of `tracing-subscriber`. The primary breaking change
+in this release is the removal of the dependency on the [`chrono` crate], due to
+[RUSTSEC-2020-0159]. To replace `chrono`, support is added for formatting
+timestamps using the [`time` crate] instead.
+
+In addition, this release includes a number of other breaking API changes, such
+as adding (limited) support for `#![no_std]` targets, removing previously
+deprecated APIs, and more.
+
+### Breaking Changes
+
+- Removed APIs deprecated in the v0.2.x release series.
+- Renamed `Layer::new_span` to `Layer::on_new_span` ([#1674])
+- Removed `Layer` impl for `Arc<L: Layer<S>>` and `Arc<dyn Layer<S> + ...>`
+  ([#1649])
+- Replaced the [`chrono` crate] with the [`time` crate] for timestamp formatting, to
+  resolve [RUSTSEC-2020-0159] ([#1646])
+- Removed `json` and `env-filter` from default features. They must now be
+  enabled explictly ([#1647]). This means that `RUST_LOG`-based filters _will not_
+  work unless the `env-filter` feature is enabled.
+- Changed `FormatEvent::format_event` and `FormatFields::format_fields`
+  trait methods to take a `Writer` type, rather than a `&mut dyn fmt::Write`
+  trait object ([#1661])
+- Changed the signature of the `MakeWriter` trait by adding a lifetime parameter
+  ([#781])
+
+### Changed
+
+- **layer**: Renamed `Layer::new_span` to `Layer::on_new_span` ([#1674])
+- **fmt**: Changed `FormatEvent::format_event` and `FormatFields::format_fields`
+  trait methods to take a `Writer` type, rather than a `&mut dyn fmt::Write`
+  trait object ([#1661])
+- **json**, **env-filter**: `json` and `env-filter` feature flags are no longer
+  enabled by default ([#1647])
+### Removed
+
+- Removed deprecated `CurrentSpan` type ([#1320])
+- **registry**: Removed deprecated `SpanRef::parents` iterator, replaced by
+  `SpanRef::scope` in [#1431] ([#1648)])
+- **layer**: Removed deprecated `Context::scope` iterator, replaced by
+  `Context::span_scope` and `Context::event_scope` in [#1431] and [#1434]
+  ([#1648)])
+- **layer**: Removed `Layer` impl for `Arc<L: Layer<S>>` and
+   `Arc<dyn Layer<S> + ...>`. These interfere with per-layer filtering. ([#1649])
+- **fmt**: Removed deprecated `LayerBuilder` type ([#1673])
+- **fmt**: Removed `fmt::Layer::on_event` (renamed to `fmt::Layer::fmt_event`)
+  ([#1673])
+- **fmt**, **chrono**: Removed the `chrono` feature flag and APIs for using the
+  [`chrono` crate] for timestamp formatting ([#1646])
+### Added
+
+- **fmt**, **time**: `LocalTime` and `UtcTime` types for formatting timestamps
+  using the [`time` crate] ([#1646])
+- **fmt**: Added a lifetime parameter to the `MakeWriter` trait, allowing it to
+  return a borrowed writer. This enables implementations of `MakeWriter` for
+  types such as `Mutex<T: io::Write>` and `std::fs::File`. ([#781])
+- **env-filter**: Documentation improvements ([#1637])
+- Support for some APIs on `#![no_std]` targets, by disabling the `std` feature
+  flag ([#1660])
+
+Thanks to @Folyd and @nmathewson for contributing to this release!
+
+[#1320]: https://github.com/tokio-rs/tracing/pull/1320
+[#1673]: https://github.com/tokio-rs/tracing/pull/1673
+[#1674]: https://github.com/tokio-rs/tracing/pull/1674
+[#1646]: https://github.com/tokio-rs/tracing/pull/1646
+[#1647]: https://github.com/tokio-rs/tracing/pull/1647
+[#1648]: https://github.com/tokio-rs/tracing/pull/1648
+[#1649]: https://github.com/tokio-rs/tracing/pull/1649
+[#1660]: https://github.com/tokio-rs/tracing/pull/1660
+[#1661]: https://github.com/tokio-rs/tracing/pull/1661
+[#1431]: https://github.com/tokio-rs/tracing/pull/1431
+[#1434]: https://github.com/tokio-rs/tracing/pull/1434
+[#781]: https://github.com/tokio-rs/tracing/pull/781
+
+[`chrono` crate]: https://crates.io/crates/chrono
+[`time` crate]: https://crates.io/crates/time
+[RUSTSEC-2020-0159]: https://rustsec.org/advisories/RUSTSEC-2020-0159.html
+
+# 0.2.25 (October 5, 2021)
+
+This release fixes an issue where a `Layer` implementation's custom
+`downcast_raw` implementation was lost when wrapping that layer with a per-layer
+filter.
+
+### Fixed
+
+- **registry**: Forward `Filtered::downcast_raw` to wrapped `Layer` ([#1619])
+
+### Added
+
+- Documentation improvements ([#1596], [#1601])
+
+Thanks to @bryanburgers for contributing to this release!
+
+[#1619]: https://github.com/tokio-rs/tracing/pull/1619
+[#1601]: https://github.com/tokio-rs/tracing/pull/1601
+[#1596]: https://github.com/tokio-rs/tracing/pull/1596
+
+# 0.2.24 (September 19, 2021)
+
+This release contains a number of bug fixes, including a fix for
+`tracing-subscriber` failing to compile on the minimum supported Rust version of
+1.42.0. It also adds `IntoIterator` implementations for the `Targets` type.
+
+### Fixed
+
+- Fixed compilation on Rust 1.42.0 ([#1580], [#1581])
+- **registry**: Ensure per-layer filter `enabled` state is cleared when a global
+  filter short-circuits filter evaluation ([#1575])
+- **layer**: Fixed `Layer::on_layer` not being called for `Box`ed `Layer`s,
+  which broke  per-layer filtering ([#1576])
+
+### Added
+
+- **filter**: Added `Targets::iter`, returning an iterator over the set of
+  target-level pairs enabled by a `Targets` filter ([#1574])
+- **filter**:  Added `IntoIterator` implementations for `Targets` and `&Targets`
+  ([#1574])
+
+Thanks to new contributor @connec for contributing to this release!
+
+[#1580]: https://github.com/tokio-rs/tracing/pull/1580
+[#1581]: https://github.com/tokio-rs/tracing/pull/1581
+[#1575]: https://github.com/tokio-rs/tracing/pull/1575
+[#1576]: https://github.com/tokio-rs/tracing/pull/1576
+[#1574]: https://github.com/tokio-rs/tracing/pull/1574
+
+# 0.2.23 (September 16, 2021)
+
+This release fixes a few bugs in the per-layer filtering API added in v0.2.21.
+
+### Fixed
+
+- **env-filter**: Fixed excessive `EnvFilter` memory use ([#1568])
+- **filter**: Fixed a panic that may occur in debug mode when using per-layer
+  filters together with global filters ([#1569])
+- Fixed incorrect documentation formatting ([#1572])
+
+[#1568]: https://github.com/tokio-rs/tracing/pull/1568
+[#1569]: https://github.com/tokio-rs/tracing/pull/1569
+[#1572]: https://github.com/tokio-rs/tracing/pull/1572
+
+# 0.2.22 (September 13, 2021)
+
+This fixes a regression where the `filter::ParseError` type was accidentally
+renamed.
+
+### Fixed
+
+- **filter**: Fix `filter::ParseError` accidentally being renamed to
+  `filter::DirectiveParseError` ([#1558])
+
+[#1558]: https://github.com/tokio-rs/tracing/pull/1558
+
+# 0.2.21 (September 12, 2021)
+
+This release introduces the [`Filter`] trait, a new API for [per-layer
+filtering][plf]. This allows controlling which spans and events are recorded by
+various layers individually, rather than globally.
+
+In addition, it adds a new [`Targets`] filter, which provides a lighter-weight
+version of the filtering provided by [`EnvFilter`], as well as other smaller API
+improvements and fixes.
+
+### Deprecated
+
+- **registry**: `SpanRef::parent_id`, which cannot properly support per-layer
+  filtering. Use `.parent().map(SpanRef::id)` instead. ([#1523])
+
+### Fixed
+
+- **layer** `Context` methods that are provided when the `Subscriber` implements
+  `LookupSpan` no longer require the "registry" feature flag ([#1525])
+- **layer** `fmt::Debug` implementation for `Layered` no longer requires the `S`
+  type parameter to implement `Debug` ([#1528])
+
+### Added
+
+- **registry**: `Filter` trait, `Filtered` type, `Layer::with_filter` method,
+  and other APIs for per-layer filtering ([#1523])
+- **filter**: `FilterFn` and `DynFilterFn` types that implement global (`Layer`)
+  and per-layer (`Filter`) filtering for closures and function pointers
+  ([#1523])
+- **filter**: `Targets` filter, which implements a lighter-weight form of
+  `EnvFilter`-like filtering ([#1550])
+- **env-filter**: Added support for filtering on floating-point values ([#1507])
+- **layer**: `Layer::on_layer` callback, called when layering the `Layer` onto a
+`Subscriber` ([#1523])
+- **layer**: `Layer` implementations for `Box<L>` and `Arc<L>` where `L: Layer`
+  ([#1536])
+- **layer**: `Layer` implementations for `Box<dyn Layer<S> + Send + Sync + 'static>`
+  and `Arc<dyn Layer<S> + Send + Sync + 'static>` ([#1536])
+- A number of small documentation fixes and improvements ([#1553], [#1544],
+  [#1539], [#1524])
+
+Special thanks to new contributors @jsgf and @maxburke for contributing to this
+release!
+
+[`Filter`]: https://docs.rs/tracing-subscriber/0.2.21/tracing_subscriber/layer/trait.Filter.html
+[plf]: https://docs.rs/tracing-subscriber/0.2.21/tracing_subscriber/layer/index.html#per-layer-filtering
+[`Targets`]: https://docs.rs/tracing-subscriber/0.2.21/tracing_subscriber/filter/struct.Targets.html
+[`EnvFilter`]: https://docs.rs/tracing-subscriber/0.2.21/tracing_subscriber/filter/struct.EnvFilter.html
+[#1507]: https://github.com/tokio-rs/tracing/pull/1507
+[#1523]: https://github.com/tokio-rs/tracing/pull/1523
+[#1524]: https://github.com/tokio-rs/tracing/pull/1524
+[#1525]: https://github.com/tokio-rs/tracing/pull/1525
+[#1528]: https://github.com/tokio-rs/tracing/pull/1528
+[#1539]: https://github.com/tokio-rs/tracing/pull/1539
+[#1544]: https://github.com/tokio-rs/tracing/pull/1544
+[#1550]: https://github.com/tokio-rs/tracing/pull/1550
+[#1553]: https://github.com/tokio-rs/tracing/pull/1553
+
+# 0.2.20 (August 17, 2021)
+
+### Fixed
+
+- **fmt**: Fixed `fmt` printing only the first `source` for errors with a chain
+  of sources ([#1460])
+- **fmt**: Fixed missing space between level and event in the `Pretty` formatter
+  ([#1498])
+- **json**: Fixed `Json` formatter not honoring `without_time` and `with_level`
+  configurations ([#1463])
+
+### Added
+
+- **registry**: Improved panic message when cloning a span whose ID doesn't
+  exist, to aid in debugging issues with multiple subscribers ([#1483])
+- **registry**: Improved documentation on span ID generation ([#1453])
+
+[#1460]: https://github.com/tokio-rs/tracing/pull/1460
+[#1483]: https://github.com/tokio-rs/tracing/pull/1483
+[#1463]: https://github.com/tokio-rs/tracing/pull/1463
+[#1453]: https://github.com/tokio-rs/tracing/pull/1453
+[#1498]: https://github.com/tokio-rs/tracing/pull/1498
+
+Thanks to new contributors @joshtriplett and @lerouxrgd, and returning
+contributor @teozkr, for contributing to this release!
+
+# 0.2.19 (June 25, 2021)
+
+### Deprecated
+
+- **registry**: `SpanRef::parents`, `SpanRef::from_root`, and `Context::scope`
+  iterators, which are replaced by new `SpanRef::scope` and `Scope::from_root`
+  iterators ([#1413])
+
+### Added
+
+- **registry**: `SpanRef::scope` method, which returns a leaf-to-root `Iterator`
+  including the leaf span ([#1413])
+- **registry**: `Scope::from_root` method, which reverses the `scope` iterator
+  to iterate root-to-leaf ([#1413])
+- **registry**: `Context::event_span` method, which looks up the parent span of
+  an event ([#1434])
+- **registry**: `Context::event_scope` method, returning a `Scope` iterator over
+  the span scope of an event ([#1434])
+- **fmt**: `MakeWriter::make_writer_for` method, which allows returning a
+  different writer based on a span or event's metadata ([#1141])
+- **fmt**: `MakeWriterExt` trait, with `with_max_level`, `with_min_level`,
+  `with_filter`, `and`, and `or_else` combinators ([#1274])
+- **fmt**: `MakeWriter` implementation for `Arc<W> where &W: io::Write`
+  ([#1274])
+
+Thanks to @teozkr and @Folyd for contributing to this release!
+
+[#1413]: https://github.com/tokio-rs/tracing/pull/1413
+[#1434]: https://github.com/tokio-rs/tracing/pull/1434
+[#1141]: https://github.com/tokio-rs/tracing/pull/1141
+[#1274]: https://github.com/tokio-rs/tracing/pull/1274
+
+# 0.2.18 (April 30, 2021)
+
+### Deprecated
+
+- Deprecated the `CurrentSpan` type, which is inefficient and largely superseded
+  by the `registry` API ([#1321])
+
+### Fixed
+
+- **json**: Invalid JSON emitted for events in spans with no fields ([#1333])
+- **json**: Missing span data for synthesized new span, exit, and close events
+  ([#1334])
+- **fmt**: Extra space before log lines when timestamps are disabled ([#1355])
+
+### Added
+
+- **env-filter**: Support for filters on spans whose names contain any
+  characters other than `{` and `]` ([#1368])
+
+Thanks to @Folyd, and new contributors @akinnane and @aym-v for contributing to
+this release!
+
+[#1321]: https://github.com/tokio-rs/tracing/pull/1321
+[#1333]: https://github.com/tokio-rs/tracing/pull/1333
+[#1334]: https://github.com/tokio-rs/tracing/pull/1334
+[#1355]: https://github.com/tokio-rs/tracing/pull/1355
+[#1368]: https://github.com/tokio-rs/tracing/pull/1368
+
+# 0.2.17 (March 12, 2021)
+
+### Fixed
+
+- **fmt**: `Pretty` formatter now honors `with_ansi(false)` to disable ANSI
+  terminal formatting ([#1240])
+- **fmt**: Fixed extra padding when using `Pretty` formatter ([#1275])
+- **chrono**: Removed extra trailing space with `ChronoLocal` time formatter
+  ([#1103])
+
+### Added
+
+- **fmt**: Added `FmtContext::current_span()` method, returning the current span
+  ([#1290])
+- **fmt**: `FmtSpan` variants may now be combined using the `|` operator for
+  more granular control over what span events are generated ([#1277])
+
+Thanks to new contributors @cratelyn, @dignati, and @zicklag, as well as @Folyd,
+@matklad, and @najamelan, for contributing to this release!
+
+[#1240]: https://github.com/tokio-rs/tracing/pull/1240
+[#1275]: https://github.com/tokio-rs/tracing/pull/1275
+[#1103]: https://github.com/tokio-rs/tracing/pull/1103
+[#1290]: https://github.com/tokio-rs/tracing/pull/1290
+[#1277]: https://github.com/tokio-rs/tracing/pull/1277
+
+# 0.2.16 (February 19, 2021)
+
+### Fixed
+
+- **env-filter**: Fixed directives where the level is in mixed case (such as
+  `Info`) failing to parse ([#1126])
+- **fmt**: Fixed `fmt::Subscriber` not providing a max-level hint ([#1251])
+- `tracing-subscriber` no longer enables `tracing` and `tracing-core`'s default
+  features ([#1144])
+  
+### Changed
+
+- **chrono**: Updated `chrono` dependency to 0.4.16 ([#1189])
+- **log**: Updated `tracing-log` dependency to 0.1.2
+
+Thanks to @salewski, @taiki-e, @davidpdrsn and @markdingram for contributing to
+this release!
+
+[#1126]: https://github.com/tokio-rs/tracing/pull/1126
+[#1251]: https://github.com/tokio-rs/tracing/pull/1251
+[#1144]: https://github.com/tokio-rs/tracing/pull/1144
+[#1189]: https://github.com/tokio-rs/tracing/pull/1189
+
+# 0.2.15 (November 2, 2020)
+
+### Fixed
+
+- **fmt**: Fixed wrong lifetime parameters on `FormatFields` impl for
+  `FmtContext` ([#1082])
+
+### Added
+
+- **fmt**: `format::Pretty`, an aesthetically pleasing, human-readable event
+  formatter for local development and user-facing CLIs ([#1080])
+- **fmt**: `FmtContext::field_format`, which returns the subscriber's field
+  formatter ([#1082])
+
+[#1082]: https://github.com/tokio-rs/tracing/pull/1082
+[#1080]: https://github.com/tokio-rs/tracing/pull/1080
+
+# 0.2.14 (October 22, 2020)
+
+### Fixed
+
+- **registry**: Fixed `Registry::new` allocating an excessively large amount of
+  memory, most of which would never be used ([#1064])
+
+### Changed
+
+- **registry**: Improved `new_span` performance by reusing `HashMap` allocations
+  for `Extensions` ([#1064])
+- **registry**: Significantly improved the performance of `Registry::enter` and
+  `Registry::exit` ([#1058])
+
+[#1064]: https://github.com/tokio-rs/tracing/pull/1064
+[#1058]: https://github.com/tokio-rs/tracing/pull/1058
+
+# 0.2.13 (October 7, 2020)
+
+### Changed
+
+- Updated `tracing-core` to 0.1.17 ([#992])
+
+### Added
+
+- **env-filter**: Added support for filtering on targets which contain dashes
+  ([#1014])
+- **env-filter**: Added a warning when creating an `EnvFilter` that contains
+  directives that would enable a level disabled by the `tracing` crate's
+  `static_max_level` features ([#1021])
+
+Thanks to @jyn514 and @bkchr for contributing to this release!
+
+[#992]: https://github.com/tokio-rs/tracing/pull/992
+[#1014]: https://github.com/tokio-rs/tracing/pull/1014
+[#1021]: https://github.com/tokio-rs/tracing/pull/1021
+
+# 0.2.12 (September 11, 2020)
+
+### Fixed
+
+- **env-filter**: Fixed a regression where `Option<Level>` lost its
+  `Into<LevelFilter>` impl ([#966])
+- **env-filter**: Fixed `EnvFilter` enabling spans that should not be enabled
+  when multiple subscribers are in use ([#927])
+
+### Changed
+
+- **json**: `format::Json` now outputs fields in a more readable order ([#892])
+- Updated `tracing-core` dependency to 0.1.16
+
+### Added
+
+- **fmt**: Add `BoxMakeWriter` for erasing the type of a `MakeWriter`
+  implementation ([#958])
+- **fmt**: Add `TestWriter` `MakeWriter` implementation to support libtest
+  output capturing ([#938])
+- **layer**: Add `Layer` impl for `Option<T> where T: Layer` ([#910])
+- **env-filter**: Add `From<Level>` impl for `Directive` ([#918])
+- Multiple documentation fixes and improvements
+
+Thanks to @Pothulapati, @samrg472, @bryanburgers, @keetonian, and @SriRamanujam
+for contributing to this release!
+
+[#927]: https://github.com/tokio-rs/tracing/pull/927
+[#966]: https://github.com/tokio-rs/tracing/pull/966
+[#958]: https://github.com/tokio-rs/tracing/pull/958
+[#892]: https://github.com/tokio-rs/tracing/pull/892
+[#938]: https://github.com/tokio-rs/tracing/pull/938
+[#910]: https://github.com/tokio-rs/tracing/pull/910
+[#918]: https://github.com/tokio-rs/tracing/pull/918
+
+# 0.2.11 (August 10, 2020)
+
+### Fixed
+
+- **env-filter**: Incorrect max level hint when filters involving span field
+  values are in use (#907)
+- **registry**: Fixed inconsistent span stacks when multiple registries are in
+  use on the same thread (#901)
+
+### Changed
+
+- **env-filter**: `regex` dependency enables fewer unused feature flags (#899)
+
+Thanks to @bdonlan and @jeromegn for contributing to this release!
+
+# 0.2.10 (July 31, 2020)
+
+### Fixed
+
+- **docs**: Incorrect formatting (#862)
+
+### Changed
+
+- **filter**: `LevelFilter` is now a re-export of the
+  `tracing_core::LevelFilter` type, it can now be used interchangably with the
+  versions in `tracing` and `tracing-core` (#853)
+- **filter**: Significant performance improvements when comparing `LevelFilter`s
+  and `Level`s (#853)
+- Updated the minimum `tracing-core` dependency to 0.1.12 (#853)
+
+### Added
+
+- **filter**: `LevelFilter` and `EnvFilter` now participate in `tracing-core`'s
+  max level hinting, improving performance significantly in some use cases where
+  levels are disabled globally (#853)
+
+# 0.2.9 (July 23, 2020)
+
+### Fixed
+
+- **fmt**: Fixed compilation failure on MSRV when the `chrono` feature is
+  disabled (#844)
+
+### Added
+
+- **fmt**: Span lookup methods defined by `layer::Context` are now also provided
+  by `FmtContext` (#834)
+
+# 0.2.8 (July 17, 2020)
+
+### Changed
+
+- **fmt**: When the `chrono` dependency is enabled, the `SystemTime` timestamp
+  formatter now emits human-readable timestamps rather than using `SystemTime`'s
+  `fmt::Debug`implementation (`chrono` is still required for customized
+  timestamp formatting) (#807)
+- **ansi**: Updated `ansi_term` dependency to 0.12 (#816)
+
+### Added
+
+- **json**: `with_span_list` method to configure the JSON formatter to include a
+  list of all spans in the current trace in formatting events (similarly to the
+  text formatter) (#741) 
+- **json**: `with_current_span` method to configure the JSON formatter to include
+  a field for the _current_ span (the leaf of the trace) in formatted events
+  (#741)
+- **fmt**: `with_thread_names` and `with_thread_ids` methods to configure
+  `fmt::Subscriber`s and `fmt::Layer`s to include the thread name and/or thread ID
+  of the current thread when formatting events (#818)
+  
+Thanks to new contributors @mockersf, @keetonian, and @Pothulapati for
+contributing to this release!
+
+# 0.2.7 (July 1, 2020)
+
+### Changed
+
+- **parking_lot**: Updated the optional `parking_lot` dependency to accept the
+  latest `parking_lot` version (#774)
+
+### Fixed
+
+- **fmt**: Fixed events with explicitly overridden parent spans being formatted
+  as though they were children of the current span (#767)
+
+### Added
+
+- **fmt**: Added the option to print synthesized events when spans are created,
+  entered, exited, and closed, including span durations (#761)
+- Documentation clarification and improvement (#762, #769)
+
+Thanks to @rkuhn, @greenwoodcm, and @Ralith for contributing to this release!
+
+# 0.2.6 (June 19, 2020)
+
+### Fixed
+
+- **fmt**: Fixed an issue in the JSON formatter where using `Span::record` would
+  result in malformed spans (#709)
+
+# 0.2.5 (April 21, 2020)
+
+### Changed
+
+- **fmt**: Bump sharded-slab dependency (#679)
+
+### Fixed
+
+- **fmt**: remove trailing space in `ChronoUtc` `format_time` (#677)
+
+# 0.2.4 (April 6, 2020)
+
+This release includes several API ergonomics improvements, including shorthand
+constructors for many types, and an extension trait for initializing subscribers
+using method-chaining style. Additionally, several bugs in less commonly used
+`fmt` APIs were fixed.
+
+### Added
+
+- **fmt**: Shorthand free functions for constructing most types in `fmt`
+  (including `tracing_subscriber::fmt()` to return a `SubscriberBuilder`,
+  `tracing_subscriber::fmt::layer()` to return a format `Layer`, etc) (#660)
+- **registry**: Shorthand free function `tracing_subscriber::registry()` to
+  construct a new registry (#660)
+- Added `SubscriberInitExt` extension trait for more ergonomic subscriber
+  initialization (#660)
+  
+### Changed
+
+- **fmt**: Moved `LayerBuilder` methods to `Layer` (#655)
+
+### Deprecated
+
+- **fmt**: `LayerBuilder`, as `Layer` now implements all builder methods (#655)
+  
+### Fixed
+
+- **fmt**: Fixed `Compact` formatter not omitting levels with
+  `with_level(false)` (#657)
+- **fmt**: Fixed `fmt::Layer` duplicating the fields for a new span if another
+  layer has already formatted its fields (#634)
+- **fmt**: Added missing space when using `record` to add new fields to a span
+  that already has fields (#659)
+- Updated outdated documentation (#647)
+
+
+# 0.2.3 (March 5, 2020)
+
+### Fixed
+
+- **env-filter**: Regression where filter directives were selected in the order
+  they were listed, rather than most specific first (#624)
+
+# 0.2.2 (February 27, 2020)
+
+### Added
+
+- **fmt**: Added `flatten_event` to `SubscriberBuilder` (#599)
+- **fmt**: Added `with_level` to `SubscriberBuilder` (#594)
+
+# 0.2.1 (February 13, 2020)
+
+### Changed
+
+- **filter**: `EnvFilter` directive selection now behaves correctly (i.e. like
+  `env_logger`) (#583)
+
+### Fixed
+
+- **filter**: Fixed `EnvFilter` incorrectly allowing less-specific filter
+  directives to enable events that are disabled by more-specific filters (#583)
+- **filter**: Multiple significant `EnvFilter` performance improvements,
+  especially when filtering events generated by `log` records (#578, #583)
+- **filter**: Replaced `BTreeMap` with `Vec` in `DirectiveSet`, improving
+  iteration performance significantly with typical numbers of filter directives
+  (#580)
+
+A big thank-you to @samschlegel for lots of help with `EnvFilter` performance
+tuning in this release!
+
+# 0.2.0 (February 4, 2020)
+
+### Breaking Changes
+
+- **fmt**: Renamed `Context` to `FmtContext` (#420, #425)
+- **fmt**: Renamed `Builder` to `SubscriberBuilder` (#420)
+- **filter**: Removed `Filter`. Use `EnvFilter` instead (#434)
+
+### Added
+
+- **registry**: `Registry`, a `Subscriber` implementation that `Layer`s can use
+  as a high-performance, in-memory span store. (#420, #425, #432, #433, #435)
+- **registry**: Added `LookupSpan` trait, implemented by `Subscriber`s to expose
+  stored span data to `Layer`s (#420)
+- **fmt**: Added `fmt::Layer`, to allow composing log formatting with other `Layer`s
+- **fmt**: Added support for JSON field and event formatting (#377, #415)
+- **filter**: Documentation for filtering directives (#554)
+
+### Changed
+
+- **fmt**: Renamed `Context` to `FmtContext` (#420, #425) (BREAKING)
+- **fmt**: Renamed `Builder` to `SubscriberBuilder` (#420) (BREAKING)
+- **fmt**: Reimplemented `fmt::Subscriber` in terms of the `Registry`
+  and `Layer`s (#420)
+
+### Removed
+
+- **filter**: Removed `Filter`. Use `EnvFilter` instead (#434) (BREAKING)
+
+### Fixed
+
+- **fmt**: Fixed memory leaks in the slab used to store per-span data
+  (3c35048)
+- **fmt**: `fmt::SubscriberBuilder::init` not setting up `log` compatibility
+  (#489)
+- **fmt**: Spans closed by a child span closing not also closing _their_
+  parents (#514)
+- **Layer**: Fixed `Layered` subscribers failing to downcast to their own type
+  (#549)
+- **Layer**: Fixed `Layer::downcast_ref` returning invalid references (#454)
+
+# 0.2.0-alpha.6 (February 3, 2020)
+
+### Fixed
+
+- **fmt**: Fixed empty `{}` printed after spans with no fields (f079f2d)
+- **fmt**: Fixed inconsistent formatting when ANSI colors are disabled (506a482)
+- **fmt**: Fixed mis-aligned levels when ANSI colors are disabled (eba1adb)
+- Fixed warnings on nightly Rust compilers (#558)
+
+# 0.2.0-alpha.5 (January 31, 2020)
+
+### Added
+
+- **env_filter**: Documentation for filtering directives (#554)
+- **registry**, **env_filter**: Updated `smallvec` dependency to 0.1 (#543)
+
+### Fixed
+
+- **registry**: Fixed a memory leak in the slab used to store per-span data
+  (3c35048)
+- **Layer**: Fixed `Layered` subscribers failing to downcast to their own type
+  (#549)
+- **fmt**: Fixed a panic when multiple layers insert `FormattedFields`
+  extensions from the same formatter type (1c3bb70)
+- **fmt**: Fixed `fmt::Layer::on_record` inserting a new `FormattedFields` when
+  formatted fields for a span already exist (1c3bb70)
+
+# 0.2.0-alpha.4 (January 11, 2020)
+
+### Fixed
+
+- **registry**: Removed inadvertently committed `dbg!` macros (#533)
+
+# 0.2.0-alpha.3 (January 10, 2020)
+
+### Added
+
+- **fmt**: Public `FormattedFields::new` constructor (#478)
+- **fmt**: Added examples to `fmt::Layer` documentation (#510)
+- Documentation now shows what feature flags are required by each API item (#525)
+
+### Fixed
+
+- **fmt**: Missing space between timestamp and level (#480)
+- **fmt**: Incorrect formatting with `with_target(false)` (#481)
+- **fmt**: `fmt::SubscriberBuilder::init` not setting up `log` compatibility
+  (#489)
+- **registry**: Spans exited out of order not being closed properly on exit
+  (#509)
+- **registry**: Memory leak when spans are closed by a child span closing (#514)
+- **registry**: Spans closed by a child span closing not also closing _their_
+  parents (#514)
+- Compilation errors with `no-default-features` (#499, #500)
+
+# 0.2.0-alpha.2 (December 8, 2019)
+
+### Added
+
+- `LookupSpans` implementation for `Layered` (#448)
+- `SpanRef::from_root` to iterate over a span's parents from the root (#460)
+- `Context::scope`, to iterate over the current context from the root (#460)
+- `Context::lookup_current`, which returns a `SpanRef` to the current
+  span's data (#460)
+
+### Changed
+
+- Lifetimes on some new `Context` methods to be less restrictive (#460)
+
+### Fixed
+
+- `Layer::downcast_ref` returning invalid references (#454)
+- Compilation failure on 32-bit platforms (#462)
+- Compilation failure with ANSI formatters (#438)
+
+# 0.2.0-alpha.1 (November 18, 2019)
+
+### Added
+
+- `Registry`, a reusable span store that `Layer`s can use a
+  high-performance, in-memory store. (#420, #425, #432, #433, #435)
+- Reimplemented `fmt::Subscriber` in terms of the `Registry`
+  and `Layer`s (#420)
+- Add benchmarks for fmt subscriber (#421)
+- Add support for JSON field and event formatting (#377, #415)
+
+### Changed
+
+- **BREAKING**: Change `fmt::format::FormatFields` and
+  `fmt::format::FormatEvent` to accept a mandatory `FmtContext`. These
+  `FormatFields` and `FormatEvent` will likely see additional breaking
+  changes in subsequent alpha. (#420, #425)
+- **BREAKING**: Removed `Filter`. Use `EnvFilter` instead (#434)
+
+### Contributers
+
+Thanks to all the contributers to this release!
+
+- @pimeys for #377 and #415
+
+# 0.1.6 (October 29, 2019)
+
+### Added
+
+- Add `init` and `try_init` functions to `FmtSubscriber` (#385)
+- Add `ChronoUtc` and `ChronoLocal` timers, RFC 3339 support (#387)
+- Add `tracing::subscriber::set_default` which sets the default
+  subscriber and returns a drop guard. This drop guard will reset the
+  dispatch on drop (#388).
+
+### Fixed
+
+- Fix default level for `EnvFilter`. Setting `RUST_LOG=target`
+  previously only the `ERROR` level, while it should enable everything.
+  `tracing-subscriber` now defaults to `TRACE` if no level is specified
+  (#401)
+- Fix `tracing-log` feature flag for init + try_init. The feature flag
+  `tracing_log` was used instead of the correct `tracing-log`. As a
+  result, both `tracing-log` and `tracing_log` needed to be specified in
+  order to initialize the global logger. Only `tracing-log` needs to be
+  specified now (#400).
+
+### Contributers
+
+Thanks to all the contributers to this release!
+
+- @emschwartz for #385, #387, #400 and #401
+- @bIgBV for #388
+
+# 0.1.5 (October 7, 2019)
+
+### Fixed
+
+- Spans not being closed properly when `FmtSubscriber::current_span` is used
+  (#371)
+
+# 0.1.4 (September 26, 2019)
+
+### Fixed
+
+- Spans entered twice on the same thread sometimes being completely exited when
+  the more deeply-nested entry is exited (#361)
+- Setting `with_ansi(false)` on `FmtSubscriber` not disabling ANSI color
+  formatting for timestamps (#354)
+- Incorrect reference counting in `FmtSubscriber` that could cause spans to not
+  be closed when all references are dropped (#366)
+
+# 0.1.3 (September 16, 2019)
+
+### Fixed
+
+- `Layered` subscribers not properly forwarding calls to `current_span`
+  (#350)
+
+# 0.1.2 (September 12, 2019)
+
+### Fixed
+
+- `EnvFilter` ignoring directives with targets that are the same number of
+  characters (#333)
+- `EnvFilter` failing to properly apply filter directives to events generated
+  from `log` records by`tracing-log` (#344)
+
+### Changed
+
+- Renamed `Filter` to `EnvFilter`, deprecated `Filter` (#339)
+- Renamed "filter" feature flag to "env-filter", deprecated "filter" (#339)
+- `FmtSubscriber` now defaults to enabling only the `INFO` level and above when
+  a max level filter or `EnvFilter` is not set (#336)
+- Made `parking_lot` dependency an opt-in feature flag (#348)
+
+### Added
+
+- `EnvFilter::add_directive` to add new directives to filters after they are
+  constructed (#334)
+- `fmt::Builder::with_max_level` to set a global level filter for a
+  `FmtSubscriber` without requiring the use of `EnvFilter` (#336)
+- `Layer` implementation for `LevelFilter` (#336)
+- `EnvFilter` now implements `fmt::Display` (#329)
+
+### Removed
+
+- Removed dependency on `crossbeam-util` (#348)
+
+# 0.1.1 (September 4, 2019)
+
+### Fixed
+
+- Potential double panic in `CurrentSpan` (#325)
+
+# 0.1.0 (September 3, 2019)
+
+- Initial release