Rust

Looks like the author missed my main complaint about Rust mutexes, which is that the lock method returns a Result. There should be a try_unlock method for when someone actually wants to handle the rather obscure failure case, and the name lock should be used for a method that panics on failure but returns a value that doesn't need to be unwrapped first. I see the current arrangement as being about as sensible as having array subscripting return a Result to handle the case of a failed bounds check.