Citizen.Await

Made a scheduler benchmark to compare performance with my PR, it’s sensibly the same. I saw my PR slightly slower (+0.5-1% CPU) at 100 000 citizen threads with a 1 second interval while, or at 10 000 citizen threads with a 1 millisecond interval while. Anyway, it’s kind of irrelevant compared to the code executed in the loop (while properly using Lua coroutines).