The stepdown thread can execute the stepdown if the resumed event is cleared by the hook just after the thread ran the wait() on it.
- The stepdown thread checks if it has to wait: checks _is_resumed_evt which is set, so it continues
- The hook calls pause()
- In pause(): the _is_resumed_evt is cleared
- In pause(): the hook waits on _is_idle_evt which it already set so it continues
- The stepdown thread runs _step_down_all()