Set the internal flag to ``True``. All waiters are awakened.

        Calling `.wait` once the flag is set will not block.

def set(self) -> None:
        """Set the internal flag to ``True``. All waiters are awakened.

        Calling `.wait` once the flag is set will not block.
        """
        if not self._value:
            self._value = True

            for fut in self._waiters:
                if not fut.done():
                    fut.set_result(None)