> Outlawing concurrent shared state means that every communication between two threads needs to be formatted as a "message" in whatever abstraction is in use. I

> Outlawing concurrent shared state means that every communication between two threads needs to be formatted as a "message" in whatever abstraction is in use. It needs to be copied, it needs to snapshot whatever data is needed to interpret it. You can't just set a flag and release the lock. That isn't how Rust works. There are mutexes, condvars, atomics, etc. in the standard library. You don't need the unsafe keyword; go nuts with them.