Busy waiting won't work, since there will potentially never run another thread that changes the thing you are waiting for (that's why e.g. in JS everything need

Busy waiting won't work, since there will potentially never run another thread that changes the thing you are waiting for (that's why e.g. in JS everything needs to be async). There might be ways to model things a bit different (like using Promises and other monadic abstractions), but things will never look the same as in a blocking environment.