Same reason as rust-lang/log#536 :

`cfg_if` is only used in a single place and `tracing` is used by many
other crates, so even removing one dependency will be beneficial.

Remove dependency `cfg-if` and replace `cfg_if::cfg_if!` with a `const
fn get_max_level_inner() -> LevelFilter` and uses `if cfg!(...)` inside.

Using if in const function is stablised in
[1.46](https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1460-2020-08-27)
so this should work fine in msrv 1.56

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>
; Conflicts:
;	tracing/Cargo.toml
;	tracing/src/level_filters.rs

Same reason as rust-lang/log#536 :

`cfg_if` is only used in a single place and `tracing` is used by many
other crates, so even removing one dependency will be beneficial.

Remove dependency `cfg-if` and replace `cfg_if::cfg_if!` with a `const
fn get_max_level_inner() -> LevelFilter` and uses `if cfg!(...)` inside.

Using if in const function is stablised in
[1.46](https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1460-2020-08-27)
so this should work fine in msrv 1.56

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>
; Conflicts:
;	tracing/Cargo.toml
;	tracing/src/level_filters.rs

# 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

# 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

# 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