def set(self):
        """set the event to triggered

        after calling this method, all greenlets waiting on the event will be
        rescheduled, and calling :meth:`wait` will not block until
        :meth:`clear` has been called
        """
        self._is_set = True
        scheduler.state.awoken_from_events.update(self._waiters)
        del self._waiters[:]