How do you encode the locking issue in the type system, it seems magical? Can you just never hold any locks when calling await, is it smart enough to know that this scheduler might move work between threads?
replies(5):
A type is “Send” if it can be moved from one thread to another, it is “Sync” if it can be simultaneously accessed from multiple threads.
These traits are automatically applied whenever the compiler knows it is safe to do so. In cases where automatic application is not possible, the developer can explicitly declare a type to have these traits, but doing so is unsafe (requires the ‘unsafe’ keyword and everything that entails).
You can read more at rustinomicon, if you are interested: https://doc.rust-lang.org/nomicon/send-and-sync.html