Replace `Mutex` with `parking_lot::Mutex` and `Arc` with `rclite::Arc`

[virtualritz]

Rationale:

• parking_lot::Mutex is the unwritten actual standard for various reasons (see Differences from the standard library Mutex). It also makes the code not being littered with unwrap()s wherever a Mutex is locked. I.e. you will find that almost all crates in the wild that need Mutex or RwLock will use the ones from parking_lot and not the ones from std. Using this is kind of a one way street as adding a feature flag means a lot of code duplication and lots of clutter in the code (i.e. worse than the aforementioned unwrap()s).

• rclite::Arc is purportedly faster than the std variant and it also uses a lot less memory (4 bytes on 64 bit systems vs 16 bytes for the std variant). This could be hidden behind a feature flag as the access syntax is the same.

[virtualritz]

If you agree I am happy to do the required changes and open a PR.

[ytanimura]

Thank you for the introduction. We would love to include it. These crates have a lot of downloads and seem reliable. There are a few things we are concerned about, such as behavior with wasm, but those can be found by turning CI in our GitLab. Please send me a pull request.

[virtualritz]

Please send me a pull request.

Done! It's now part of #48.

[virtualritz]

Fixed with merge of #48.