Unhelpful response. This cuongle.dev article does not answer nextaccountic's question, and neither do the webkit.org articles that describe the parking lot concept but not this Rust implementation. The correct answer appears to be that it's impossible: `parking_lot::RawMutex` has private storage that owns the entire byte and does not provide any accessor for the unused six bits.

https://docs.rs/parking_lot/0.12.5/parking_lot/struct.RawMut...

(unless there's somewhere else in the crate that provides an accessor for this but that'd be a weird interface)

(or you just use transmute to "know" that it's one byte and which bits within the byte it actually cares about, but really don't do that)

(slightly more realistically, you could probably use the `parking_lot_core::park` portion of the implementation and build your own equivalent of `parking_lot::RawMutex` on top of it)

(or you send the `parking_lot` folks a PR to extend `parking_lot::RawMutex` with interface you want; it is open source after all)