tracing: prepare to release v0.1.38 (tokio-rs#2575)

# 0.1.38 (April 25th, 2023)

This `tracing` release changes the `Drop` implementation for
`Instrumented` `Future`s so that the attached `Span` is entered when
dropping the `Future`. This means that events emitted by the `Future`'s
`Drop` implementation will now be recorded within its `Span`. It also
adds `#[inline]` hints to methods called in the `event!` macro's
expansion, for an improvement in both binary size and performance.

Additionally, this release updates the `tracing-attributes` dependency
to [v0.1.24][attrs-0.1.24], which updates the [`syn`] dependency to
v2.x.x. `tracing-attributes` v0.1.24 also includes improvements to the
`#[instrument]` macro; see [the `tracing-attributes` 0.1.24 release
notes][attrs-0.1.24] for details.

### Added

- `Instrumented` futures will now enter the attached `Span` in their
  `Drop` implementation, allowing events emitted when dropping the
  future to occur within the span (tokio-rs#2562)
- `#[inline]` attributes for methods called by the `event!` macros,
  making generated code smaller (tokio-rs#2555)
- **attributes**: `level` argument to `#[instrument(err)]` and
  `#[instrument(ret)]` to override the level of the generated return
  value event (tokio-rs#2335)
- **attributes**: Improved compiler error message when `#[instrument]`
  is added to a `const fn` (tokio-rs#2418)

### Changed

- `tracing-attributes`: updated to [0.1.24][attrs-0.1.24]
- Removed unneeded `cfg-if` dependency (tokio-rs#2553)
- **attributes**: Updated [`syn`] dependency to 2.0 (tokio-rs#2516)

### Fixed

- **attributes**: Fix `clippy::unreachable` warnings in
  `#[instrument]`-generated code (tokio-rs#2356)
- **attributes**: Removed unused "visit" feature flag from `syn`
  dependency (tokio-rs#2530)

### Documented

- **attributes**: Documented default level for `#[instrument(err)]`
  (tokio-rs#2433)
- **attributes**: Improved documentation for levels in `#[instrument]`
  (tokio-rs#2350)

Thanks to @nitnelave, @jsgf, @Abhicodes-crypto, @LukeMathWalker,
@andrewpollack, @quad, @klensy, @davidpdrsn, @dbidwell94, @ldm0,
@NobodyXu, @ilsv, and @daxpedda for contributing to this release!

[`syn`]: https://crates.io/crates/syn
[attrs-0.1.24]:
    https://github.com/tokio-rs/tracing/releases/tag/tracing-attributes-0.1.24

tracing/CHANGELOG.md

@@ -1,3 +1,65 @@
+# 0.1.38 (April 25th, 2023)
+
+This `tracing` release changes the `Drop` implementation for `Instrumented`
+`Future`s so that the attached `Span` is entered when dropping the `Future`. This
+means that events emitted by the `Future`'s `Drop` implementation will now be
+recorded within its `Span`. It also adds `#[inline]` hints to methods called in
+the `event!` macro's expansion, for an improvement in both binary size and
+performance.
+
+Additionally, this release updates the `tracing-attributes` dependency to
+[v0.1.24][attrs-0.1.24], which updates the [`syn`] dependency to v2.x.x.
+`tracing-attributes` v0.1.24 also includes improvements to the `#[instrument]`
+macro; see [the `tracing-attributes` 0.1.24 release notes][attrs-0.1.24] for
+details.
+
+### Added
+
+- `Instrumented` futures will now enter the attached `Span` in their `Drop`
+  implementation, allowing events emitted when dropping the future to occur
+  within the span ([#2562])
+- `#[inline]` attributes for methods called by the `event!` macros, making
+  generated code smaller ([#2555])
+- **attributes**: `level` argument to `#[instrument(err)]` and
+  `#[instrument(ret)]` to override the level of
+  the generated return value event ([#2335])
+- **attributes**: Improved compiler error message when `#[instrument]` is added to a `const fn`
+  ([#2418])
+
+### Changed
+
+- `tracing-attributes`: updated to [0.1.24][attrs-0.1.24]
+- Removed unneeded `cfg-if` dependency ([#2553])
+- **attributes**: Updated [`syn`] dependency to 2.0 ([#2516])
+
+### Fixed
+
+- **attributes**: Fix `clippy::unreachable` warnings in `#[instrument]`-generated code ([#2356])
+- **attributes**: Removed unused "visit" feature flag from `syn` dependency ([#2530])
+
+### Documented
+
+- **attributes**: Documented default level for `#[instrument(err)]` ([#2433])
+- **attributes**: Improved documentation for levels in `#[instrument]` ([#2350])
+
+Thanks to @nitnelave, @jsgf, @Abhicodes-crypto, @LukeMathWalker, @andrewpollack,
+@quad, @klensy, @davidpdrsn, @dbidwell94, @ldm0, @NobodyXu, @ilsv, and @daxpedda
+for contributing to this release!
+
+[`syn`]: https://crates.io/crates/syn
+[attrs-0.1.24]:
+    https://github.com/tokio-rs/tracing/releases/tag/tracing-attributes-0.1.24
+[#2565]: https://github.com/tokio-rs/tracing/pull/2565
+[#2555]: https://github.com/tokio-rs/tracing/pull/2555
+[#2553]: https://github.com/tokio-rs/tracing/pull/2553
+[#2335]: https://github.com/tokio-rs/tracing/pull/2335
+[#2418]: https://github.com/tokio-rs/tracing/pull/2418
+[#2516]: https://github.com/tokio-rs/tracing/pull/2516
+[#2356]: https://github.com/tokio-rs/tracing/pull/2356
+[#2530]: https://github.com/tokio-rs/tracing/pull/2530
+[#2433]: https://github.com/tokio-rs/tracing/pull/2433
+[#2350]: https://github.com/tokio-rs/tracing/pull/2350
+
 # 0.1.37 (October 6, 2022)
 
 This release of `tracing` incorporates changes from `tracing-core`

tracing/README.md

@@ -98,7 +98,7 @@ fn main() {
 ```toml
 [dependencies]
 tracing = "0.1"
-tracing-subscriber = "0.2.0"
+tracing-subscriber = "0.3.0"
 ```
 
 This subscriber will be used as the default in all threads for the remainder of the duration
@@ -250,7 +250,7 @@ my_future
 is as long as the future's.
 
 The second, and preferred, option is through the
-[`#[instrument]`](https://docs.rs/tracing/0.1.37/tracing/attr.instrument.html)
+[`#[instrument]`](https://docs.rs/tracing/0.1.38/tracing/attr.instrument.html)
 attribute:
 
 ```rust
@@ -297,7 +297,7 @@ span.in_scope(|| {
 // Dropping the span will close it, indicating that it has ended.
 ```
 
-The [`#[instrument]`](https://docs.rs/tracing/0.1.37/tracing/attr.instrument.html) attribute macro
+The [`#[instrument]`](https://docs.rs/tracing/0.1.38/tracing/attr.instrument.html) attribute macro
 can reduce some of this boilerplate:
 
 ```rust