* Update `tracing`-related dependencies
* Enable `parking_lot` feature in `tracing-subscriber`
* Add an asynchronous stderr logger
* Make clippy happy
* Add an integration test for the logger
* Refactor `test_logger_filters`'s subprocess machinery into a separate function
* Use a child process instead of hooking into stderr for the test
* Add a doc comment for `MakeStderrWriter`
* Move the initialization into the `MakeStderrWriter`'s constructor
* Add an extra test case to trigger the logger's emergency flush mechanism
* Use the buffer's mutex for asynchronous flushes
* Remove vestigial `nix` dependency from one of the previous commits
Koute
3d5f093ddb