If the Task isn't started yet, execute it in the current thread.
If it's done, return its return value, if any. If it's in progress,
busy spin until it's done, then return the return value. If it threw
an exception, rethrow that exception.
This function should be used when you expect the result of the
Task to be available on a timescale shorter than that of an OS
context switch.
If the Task isn't started yet, execute it in the current thread. If it's done, return its return value, if any. If it's in progress, busy spin until it's done, then return the return value. If it threw an exception, rethrow that exception.
This function should be used when you expect the result of the Task to be available on a timescale shorter than that of an OS context switch.