# 0.3.23 (March 13, 2026)### Fixed- Allow ansi sanitization to be disabled ([#3484])[#3484]: https://github.com/tokio-rs/tracing/pull/3484# 0.3.22 (November 28, 2025)#### ImportantThe previous release [0.3.21] was yanked as it depended explicitly on[tracing-0.1.42], which was yanked due to a breaking change (see [#3424] fordetails). This release contains all the changes from the previous release, plusan update to the newer version of `tracing`.### Changed- `tracing`: updated to 0.1.43 ([#3427])[#3424]: https://github.com/tokio-rs/tracing/pull/3424[#3427]: https://github.com/tokio-rs/tracing/pull/3427[0.3.21]: https://github.com/tokio-rs/tracing/releases/tag/tracing-subscriber-0.3.21[tracing-0.1.42]: https://github.com/tokio-rs/tracing/releases/tag/tracing-0.1.42# 0.3.21 (November 26, 2025)### Fixed- Change registry exit to decrement local span ref only ([#3331])- Make Layered propagate `on_register_dispatch` ([#3379])### Changed- `tracing`: updated to 0.1.42 ([#3418])### Performance- Remove `clone_span` on enter ([#3289]) ### Documented- Fix a few small things in the format module ([#3339])- Fix extra closing brace in layer docs ([#3350])- Fix link in `FmtSpan` docs ([#3411])[#3289]: https://github.com/tokio-rs/tracing/pull/3289[#3331]: https://github.com/tokio-rs/tracing/pull/3331[#3339]: https://github.com/tokio-rs/tracing/pull/3339[#3350]: https://github.com/tokio-rs/tracing/pull/3350[#3379]: https://github.com/tokio-rs/tracing/pull/3379[#3411]: https://github.com/tokio-rs/tracing/pull/3411[#3418]: https://github.com/tokio-rs/tracing/pull/3418# 0.3.20 (August 29, 2025)[ [crates.io][crate-0.3.20] ] | [ [docs.rs][docs-0.3.20] ]### Fixed- Escape ANSI escape sequences in logs ([#3368])### Added- Implement `Clone` for `EnvFilter` ([#3360])[#3360]: https://github.com/tokio-rs/tracing/pull/3360[#3368]: https://github.com/tokio-rs/tracing/pull/3368[docs-0.3.20]: https://docs.rs/tracing-subscriber/0.3.20/tracing_subscriber/[crate-0.3.20]: https://crates.io/crates/tracing-subscriber/0.3.20# 0.3.19 (November 29, 2024)[ [crates.io][crate-0.3.19] ] | [ [docs.rs][docs-0.3.19] ]This release updates the `tracing` dependency to [v0.1.41][tracing-0.1.41] andthe `tracing-serde` dependency to [v0.2.0][tracing-serde-0.2.0].### Added- Add `set_span_events` to `fmt::Subscriber` ([#2962])- **tracing**: Allow `&[u8]` to be recorded as event/span field ([#2954])### Changed- Set `log` max level when reloading ([#1270])- Bump MSRV to 1.63 ([#2793])- Use const `thread_local`s when possible ([#2838])- Don't gate `with_ansi()` on the "ansi" feature ([#3020])- Updated tracing-serde to 0.2.0 ([#3160])[#1270]: https://github.com/tokio-rs/tracing/pull/1270[#2793]: https://github.com/tokio-rs/tracing/pull/2793[#2838]: https://github.com/tokio-rs/tracing/pull/2838[#2954]: https://github.com/tokio-rs/tracing/pull/2954[#2962]: https://github.com/tokio-rs/tracing/pull/2962[#3020]: https://github.com/tokio-rs/tracing/pull/3020[#3160]: https://github.com/tokio-rs/tracing/pull/3160[tracing-0.1.41]:    https://github.com/tokio-rs/tracing/releases/tag/tracing-0.1.41[tracing-serde-0.2.0]:    https://github.com/tokio-rs/tracing/releases/tag/tracing-serde-0.2.0[docs-0.3.19]: https://docs.rs/tracing-subscriber/0.3.19/tracing_subscriber/[crate-0.3.19]: https://crates.io/crates/tracing-subscriber/0.3.19# 0.3.18 (November 13, 2023)This release of `tracing-subscriber` adds support for the [`NO_COLOR`] environmentvariable (an informal standard to disable emitting ANSI color escape codes) in`fmt::Layer`, reintroduces support for the [`chrono`] crate, and increases theminimum supported Rust version (MSRV) to Rust 1.63.0.It also introduces several minor API improvements.### Added- **chrono**: Add [`chrono`] implementations of `FormatTime` ([#2690])- **subscriber**: Add support for the [`NO_COLOR`] environment variable in`fmt::Layer` ([#2647])- **fmt**: make `format::Writer::new()` public ([#2680])- **filter**: Implement `layer::Filter` for `Option<Filter>` ([#2407])### Changed- **log**: bump version of `tracing-log` to 0.2 ([#2772])- Increased minimum supported Rust version (MSRV) to 1.63.0+.[`chrono`]: https://github.com/chronotope/chrono[`NO_COLOR`]: https://no-color.org/[#2690]: https://github.com/tokio-rs/tracing/pull/2690[#2647]: https://github.com/tokio-rs/tracing/pull/2647[#2680]: https://github.com/tokio-rs/tracing/pull/2680[#2407]: https://github.com/tokio-rs/tracing/pull/2407[#2772]: https://github.com/tokio-rs/tracing/pull/2772Thanks to @shayne-fletcher, @dmlary, @kaifastromai, and @jsgf for contributing!# 0.3.17 (April 21, 2023)This release of `tracing-subscriber` fixes a build error when using `env-filter`with recent versions of the `regex` crate. It also introduces several minor APIimprovements.### Fixed- **env-filter**: Add "unicode-case" and "unicode-perl" to the `regex`  dependency, fixing a build error with recent versions of `regex` ([#2566])- A number of minor documentation typos and other fixes ([#2384], [#2378],  [#2368], [#2548])### Added- **filter**: Add `fmt::Display` impl for `filter::Targets` ([#2343])- **fmt**: Made `with_ansi(false)` no longer require the "ansi" feature, so that  ANSI formatting escapes can be disabled without requiring ANSI-specific  dependencies ([#2532])### Changed- **fmt**: Dim targets in the `Compact` formatter, matching the default  formatter ([#2409])Thanks to @keepsimple1, @andrewhalle, @LeoniePhiline, @LukeMathWalker,@howardjohn, @daxpedda, and @dbidwell94 for contributing to this release![#2566]: https://github.com/tokio-rs/tracing/pull/2566[#2384]: https://github.com/tokio-rs/tracing/pull/2384[#2378]: https://github.com/tokio-rs/tracing/pull/2378[#2368]: https://github.com/tokio-rs/tracing/pull/2368[#2548]: https://github.com/tokio-rs/tracing/pull/2548[#2343]: https://github.com/tokio-rs/tracing/pull/2343[#2532]: https://github.com/tokio-rs/tracing/pull/2532[#2409]: https://github.com/tokio-rs/tracing/pull/2409# 0.3.16 (October 6, 2022)This release of `tracing-subscriber` fixes a regression introduced in[v0.3.15][subscriber-0.3.15] where `Option::None`'s `Layer` implementation wouldset the max level hint to `OFF`. In addition, it adds several new APIs,including the `Filter::event_enabled` method for filtering events based onfields values, and the ability to log internal errors that occur when writing alog line.This release also replaces the dependency on the unmaintained [`ansi-term`]crate with the [`nu-ansi-term`] crate, resolving an *informational* securityadvisory ([RUSTSEC-2021-0139]) for [`ansi-term`]'s maintainance status. Thisincreases the minimum supported Rust version (MSRV) to Rust 1.50+, although thecrate should still compile for the previous MSRV of Rust 1.49+ when the `ansi`feature is not enabled.### Fixed- **layer**: `Option::None`'s `Layer` impl always setting the `max_level_hint`  to `LevelFilter::OFF` ([#2321])- Compilation with `-Z minimal versions` ([#2246])- **env-filter**: Clarify that disabled level warnings are emitted by  `tracing-subscriber` ([#2285])### Added- **fmt**: Log internal errors to `stderr` if writing a log line fails ([#2102])- **fmt**: `FmtLayer::log_internal_errors` and  `FmtSubscriber::log_internal_errors` methods for configuring whether internal  writer errors are printed to `stderr` ([#2102])- **fmt**: `#[must_use]` attributes on builders to warn if a `Subscriber` is  configured but not set as the default subscriber ([#2239])- **filter**: `Filter::event_enabled` method for filtering an event based on its  fields ([#2245], [#2251])- **filter**: `Targets::default_level` accessor ([#2242])### Changed- **ansi**: Replaced dependency on unmaintained `ansi-term` crate with  `nu-ansi-term` (([#2287], fixes informational advisory [RUSTSEC-2021-0139])- `tracing-core`: updated to [0.1.30][core-0.1.30]- Minimum Supported Rust Version (MSRV) increased to Rust 1.50+ (when the  `ansi`) feature flag is enabled ([#2287])### Documented- **fmt**: Correct inaccuracies in `fmt::init` documentation ([#2224])- **filter**: Fix incorrect doc link in `filter::Not` combinator ([#2249])Thanks to new contributors @cgbur, @DesmondWillowbrook, @RalfJung, and@poliorcetics, as well as returning contributors @CAD97, @connec, @jswrenn,@guswynn, and @bryangarza, for contributing to this release![nu-ansi-term]: https://github.com/nushell/nu-ansi-term[ansi_term]: https://github.com/ogham/rust-ansi-term[RUSTSEC-2021-0139]: https://rustsec.org/advisories/RUSTSEC-2021-0139.html[core-0.1.30]: https://github.com/tokio-rs/tracing/releases/tag/tracing-core-0.1.30[subscriber-0.3.15]: https://github.com/tokio-rs/tracing/releases/tag/tracing-subscriber-0.3.15[#2321]: https://github.com/tokio-rs/tracing/pull/2321[#2246]: https://github.com/tokio-rs/tracing/pull/2246[#2285]: https://github.com/tokio-rs/tracing/pull/2285[#2102]: https://github.com/tokio-rs/tracing/pull/2102[#2239]: https://github.com/tokio-rs/tracing/pull/2239[#2245]: https://github.com/tokio-rs/tracing/pull/2245[#2251]: https://github.com/tokio-rs/tracing/pull/2251[#2287]: https://github.com/tokio-rs/tracing/pull/2287[#2224]: https://github.com/tokio-rs/tracing/pull/2224[#2249]: https://github.com/tokio-rs/tracing/pull/2249# 0.3.15 (Jul 20, 2022)This release fixes a bug where the `reload` layer would fail to pass through`max_level_hint` to the underlying layer, potentially breaking filtering.### Fixed- **reload**: pass through `max_level_hint` to the inner `Layer` ([#2204])Thanks to @guswynn for contributing to this release![#2204]: https://github.com/tokio-rs/tracing/pull/2204# 0.3.14 (Jul 1, 2022)This release fixes multiple filtering bugs in the `Layer` implementations for`Option<impl Layer>` and `Vec<impl Layer>`.### Fixed- **layer**: `Layer::event_enabled` implementation for `Option<impl Layer<S>>`  returning `false` when the `Option` is `None`, disabling all events globally  ([#2193])- **layer**: `Layer::max_level_hint` implementation for `Option<impl Layer<S>>`  incorrectly disabling max level filtering when the option is `None` ([#2195])- **layer**: `Layer::max_level_hint` implementation for `Vec<impl Layer<S>>`  returning `LevelFilter::ERROR` rather than `LevelFilter::OFF` when the `Vec`  is empty ([#2195])Thanks to @CAD97 and @guswynn for contributing to this release![#2193]: https://github.com/tokio-rs/tracing/pull/2193[#2195]: https://github.com/tokio-rs/tracing/pull/2195# 0.3.13 (Jun 30, 2022) (YANKED)This release of `tracing-subscriber` fixes a compilation failure due to anincorrect `tracing-core` dependency that was introduced in v0.3.12.### Changed- **tracing_core**: Updated minimum dependency version to 0.1.28 ([#2190])[#2190]: https://github.com/tokio-rs/tracing/pull/2190# 0.3.12 (Jun 29, 2022) (YANKED)This release of `tracing-subscriber` adds a new `Layer::event_enabled` method,which allows `Layer`s to filter events *after* their field values are recorded;a `Filter` implementation for `reload::Layer`, to make using `reload` withper-layer filtering more ergonomic, and additional inherent method downcastingAPIs for the `Layered` type. In addition, it includes dependency updates, andminor fixes for documentation and feature flagging.### Added- **layer**: `Layer::event_enabled` method, which can be implemented to filter  events based on their field values ([#2008])- **reload**: `Filter` implementation for `reload::Layer` ([#2159])- **layer**: `Layered::downcast_ref` and `Layered::is` inherent methods  ([#2160])### Changed- **parking_lot**: Updated dependency on `parking_lot` to 0.13.0 ([#2143])- Replaced `lazy_static` dependency with `once_cell` ([#2147])### Fixed- Don't enable `tracing-core` features by default ([#2107])- Several documentation link and typo fixes ([#2064], [#2068], #[2077], [#2161],  [#1088])Thanks to @ben0x539, @jamesmunns, @georgemp, @james7132, @jswrenn, @CAD97, and@guswynn for contributing to this release![#2008]: https://github.com/tokio-rs/tracing/pull/2008[#2159]: https://github.com/tokio-rs/tracing/pull/2159[#2160]: https://github.com/tokio-rs/tracing/pull/2160[#2143]: https://github.com/tokio-rs/tracing/pull/2143[#2107]: https://github.com/tokio-rs/tracing/pull/2107[#2064]: https://github.com/tokio-rs/tracing/pull/2064[#2068]: https://github.com/tokio-rs/tracing/pull/2068[#2077]: https://github.com/tokio-rs/tracing/pull/2077[#2161]: https://github.com/tokio-rs/tracing/pull/2161[#1088]: https://github.com/tokio-rs/tracing/pull/1088# 0.3.11 (Apr 9, 2022)This is a bugfix release for the `Filter` implementation for `EnvFilter` addedin [v0.3.10].### Fixed- **env-filter**: Added missing `Filter::on_record` callback to `EnvFilter`'s  `Filter` impl ([#2058])- **env-filter**: Fixed method resolution issues when calling `EnvFilter`  methods with both the `Filter` and `Layer` traits in scope ([#2057])- **env-filter**: Fixed `EnvFilter::builder().parse()` and other parsing methods  returning an error when parsing an empty string ([#2052])Thanks to new contributor @Ma124 for contributing to this release![v0.3.10]: https://github.com/tokio-rs/tracing/releases/tag/tracing-subscriber-0.3.10[#2058]: https://github.com/tokio-rs/tracing/pull/2058[#2057]: https://github.com/tokio-rs/tracing/pull/2057[#2052]: https://github.com/tokio-rs/tracing/pull/2052# 0.3.10 (Apr 1, 2022)This release adds several new features, including a `Filter` implementation andnew builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` asa `Layer`, and a number of smaller API improvements to make working with dynamicand reloadable layers easier.### Added- **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with  per-layer filtering ([#1983])- **registry**: `Filter::on_new_span`, `Filter::on_enter`,  `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to  allow `Filter`s to track span states internally ([#1973], [#2017], [#2031])- **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors  ([#1959])- **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow  the wrapped `Layer` ([#2034])- **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together  a dynamically sized list of `Layer`s ([#2027])- **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier  ([#2026])- **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034])- **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting  configuration at runtime ([#2034])- **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to  parsing it ([#2035])- Several documentation fixes and improvements ([#1972], [#1971], [#2023],  [#2023])### Fixed- **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type  parameter's auto traits ([#2025])- **env-filter**: Fixed missing help text when the `ansi` feature is disabled  ([#2029])Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 forcontributing to this release![#1983]: https://github.com/tokio-rs/tracing/pull/1983[#1973]: https://github.com/tokio-rs/tracing/pull/1973[#2017]: https://github.com/tokio-rs/tracing/pull/2017[#2031]: https://github.com/tokio-rs/tracing/pull/2031[#1959]: https://github.com/tokio-rs/tracing/pull/1959[#2034]: https://github.com/tokio-rs/tracing/pull/2034[#2027]: https://github.com/tokio-rs/tracing/pull/2027[#2026]: https://github.com/tokio-rs/tracing/pull/2026[#2035]: https://github.com/tokio-rs/tracing/pull/2035[#1972]: https://github.com/tokio-rs/tracing/pull/1972[#1971]: https://github.com/tokio-rs/tracing/pull/1971[#2023]: https://github.com/tokio-rs/tracing/pull/2023[#2025]: https://github.com/tokio-rs/tracing/pull/2025[#2029]: https://github.com/tokio-rs/tracing/pull/2029# 0.3.9 (Feb 17, 2022)This release updates the minimum supported Rust version (MSRV) to 1.49.0, andupdates the (optional) dependency on `parking_lot` to v0.12.### Changed- Updated minimum supported Rust version (MSRV) to 1.49.0 ([#1913])- `parking_lot`: updated to v0.12 ([008339d])### Added- **fmt**: Documentation improvements ([#1926], [#1927])[#1913]: https://github.com/tokio-rs/tracing/pull/1913[#1926]: https://github.com/tokio-rs/tracing/pull/1926[#1927]: https://github.com/tokio-rs/tracing/pull/1927[008339d]: https://github.com/tokio-rs/tracing/commit/008339d1e8750ffe7b4634fc7789bda0c522424f# 0.3.8 (Feb 4, 2022)This release adds *experimental* support for recording structured fieldvalues using the [`valuable`] crate to the `format::Json` formatter. Inparticular, user-defined types which are recorded using their[`valuable::Valuable`] implementations will be serialized as JSON objects,rather than using their `fmt::Debug` representation. See [this blog post][post]for details on `valuable`.Note that `valuable` support currently requires `--cfg tracing_unstable`. Seethe documentation for details.Additionally, this release includes a number of other smaller API improvements.### Added- **json**: Experimental support for recording [`valuable`] values as structured  JSON ([#1862], [#1901])- **filter**: `Targets::would_enable` method for testing if a `Targets` filter  would enable a given target ([#1903])- **fmt**: `map_event_format`, `map_fmt_fields`, and `map_writer` methods to  `fmt::Layer` and `fmt::SubscriberBuilder` ([#1871])### Changed- `tracing-core`: updated to [0.1.22][core-0.1.22]### Fixed- Set `smallvec` minimal version to 1.2.0, to fix compilation errors with `-Z  minimal-versions` ([#1890])- Minor documentation fixes ([#1902], [#1893])Thanks to @guswynn, @glts, and @lilyball for contributing to this release![`valuable`]: https://crates.io/crates/valuable[`valuable::Valuable`]: https://docs.rs/valuable/latest/valuable/trait.Valuable.html[post]: https://tokio.rs/blog/2021-05-valuable[core-0.1.22]: https://github.com/tokio-rs/tracing/releases/tag/tracing-core-0.1.22[#1862]: https://github.com/tokio-rs/tracing/pull/1862[#1901]: https://github.com/tokio-rs/tracing/pull/1901[#1903]: https://github.com/tokio-rs/tracing/pull/1903[#1871]: https://github.com/tokio-rs/tracing/pull/1871[#1890]: https://github.com/tokio-rs/tracing/pull/1890[#1902]: https://github.com/tokio-rs/tracing/pull/1902[#1893]: https://github.com/tokio-rs/tracing/pull/1893# 0.3.7 (Jan 25, 2022)This release adds combinators for combining filters.Additionally, this release also updates the `thread-local` crate to v1.1.4,fixing warnings for the security advisory [RUSTSEC-2022-0006]. Note thatprevious versions of `tracing-subscriber` did not use any of the `thread-local`crate's APIs effected by the vulnerability. However, updating the version fixeswarnings emitted by `cargo audit` and similar tools.### Added- **filter**: Added combinators for combining filters ([#1578])### Fixed- **registry**: Updated `thread-local` to v1.1.4 ([#1858])Thanks to new contributor @matze for contributing to this release![RUSTSEC-2022-0006]: https://rustsec.org/advisories/RUSTSEC-2022-0006[#1578]: https://github.com/tokio-rs/tracing/pull/1578[#1858]: https://github.com/tokio-rs/tracing/pull/1858# 0.3.6 (Jan 14, 2022)This release adds configuration options to `tracing_subscriber::fmt` to logsource code locations for events.### Added- **fmt**: Added `with_file` and `with_line_number`  configuration methods to `fmt::Format`, `fmt::SubscriberBuilder`, and  `fmt::Layer` ([#1773])### Fixed- **fmt**: Removed incorrect leading comma from span fields with the `Pretty`  formatter ([#1833])### Deprecated- **fmt**: Deprecated `Pretty::with_source_location`, as it can now be replaced  by the more general `Format`, `SubscriberBuilder`, and `Layer` methods  ([#1773])Thanks to new contributor @renecouto for contributing to this release![#1773]: https://github.com/tokio-rs/tracing/pull/1773[#1833]: https://github.com/tokio-rs/tracing/pull/1833# 0.3.5 (Dec 29, 2021)This release re-enables `RUST_LOG` filtering in `tracing_subscriber::fmt`'sdefault initialization methods, and adds an `OffsetLocalTime` formatter forusing local timestamps with the `time` crate.### Added- **fmt**: Added `OffsetLocalTime` formatter to `fmt::time` for formatting local  timestamps with a fixed offset ([#1772])### Fixed- **fmt**: Added a `Targets` filter to `fmt::init()` and `fmt::try_init()` when  the "env-filter" feature is disabled, so that `RUST_LOG` is still honored  ([#1781])Thanks to @marienz and @ishitatsuyuki for contributing to this release![#1772]: https://github.com/tokio-rs/tracing/pull/1772[#1781]: https://github.com/tokio-rs/tracing/pull/1781# 0.3.4 (Dec 23, 2021) This release contains bugfixes for the `fmt` module, as well as documentationimprovements.### Fixed- **fmt**: Fixed `fmt` not emitting log lines when timestamp formatting fails  ([#1689])- **fmt**: Fixed double space before thread IDs with `Pretty` formatter  ([#1778])- Several documentation improvements ([#1608], [#1699], [#1701])[#1689]: https://github.com/tokio-rs/tracing/pull/1689[#1778]: https://github.com/tokio-rs/tracing/pull/1778[#1608]: https://github.com/tokio-rs/tracing/pull/1608[#1699]: https://github.com/tokio-rs/tracing/pull/1699[#1701]: https://github.com/tokio-rs/tracing/pull/1701Thanks to new contributors @Swatinem and @rukai for contributing to thisrelease!# 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 changein this release is the removal of the dependency on the [`chrono` crate], due to[RUSTSEC-2020-0159]. To replace `chrono`, support is added for formattingtimestamps using the [`time` crate] instead.In addition, this release includes a number of other breaking API changes, suchas adding (limited) support for `#![no_std]` targets, removing previouslydeprecated 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-layerfilter.### 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 of1.42.0. 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 accidentallyrenamed.### 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-layerfiltering][plf]. This allows controlling which spans and events are recorded byvarious layers individually, rather than globally.In addition, it adds a new [`Targets`] filter, which provides a lighter-weightversion of the filtering provided by [`EnvFilter`], as well as other smaller APIimprovements 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 thisrelease![`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/1498Thanks to new contributors @joshtriplett and @lerouxrgd, and returningcontributor @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 tothis 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 0.1.2Thanks to @salewski, @taiki-e, @davidpdrsn and @markdingram for contributing tothis 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 improvementsThanks to @Pothulapati, @samrg472, @bryanburgers, @keetonian, and @SriRamanujamfor 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 interchangeably 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 forcontributing 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 shorthandconstructors for many types, and an extension trait for initializing subscribersusing 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` performancetuning 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 misaligned 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)### ContributorsThanks to all the contributors 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).### ContributorsThanks to all the contributors 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