a timeout value for an idle loop. There is no guarantee you won't return earlier or later than this; the function might run longer than the timeout if it has work to do. Pass Duration.max (the default) for an infinite duration timeout (but remember, once it finds work to do, including a false-positive wakeup or interruption by the operating system, it will return early anyway).
Prior to December 28, 2023, it returned void and took no arguments. This change is breaking, but since the entire module is documented as unstable, it was permitted to happen as that document provided prior notice.
Runs a single iteration of the event loop for this thread. It will return when the first thing happens, but that thing might be totally uninteresting to anyone, or it might trigger significant work you'll wait on.
Note that running this externally instead of run gives only the illusion of control. You're actually better off setting a recurring timer if you need things to run on a clock tick, or a single-shot timer for a one time event. They're more likely to be called on schedule inside this function than outside it.