Trial Spawners activating/deactivating should be detectable by observers.

Trial spawners activating/deactivating should be detectable by observers. I don’t know if this is possible as I don’t know if trial spawners change their block state when activating/deactivating. If they do, this would be a neat feature to add to them. This would be useful for mapmakers. Example: Imagine a room in an adventure map where a player can’t leave and has to fight a bunch of mobs spawned by a trial spawner. Once all the mobs are killed and the trial spawner deactivates, an observer detects that and sends a redstone signal; opening the door to leave.