I've used Smithay's Rust client toolkit for a few months now. For making apps it is still sometimes have unsafe wrappers disguised as safe. It has a lot of internals wrapped in Arc<>, but in my tests, the methods are not safe to call from different threads anyhow, you will get weird crashes if done so.

I will seek to dive-in to how Wayland API actually works, because I'd really like to know what not to do, when the wrappers used 'wrong' can crash.