I have seen one small bug im not sure if it is supposed to happen this way. When a notification is fired and gets consumed by say 7 listeners it will act as expected untill say listener 5 fires a second Notification. Notification 1 now stops while Notification 2 completes then the paused notification 1 starts from where it left off.
Im not sure if this is what you intend but i think it would make more sense if the notifications were kept in a stack and once notification 1 is fully complete, then notification 2 will get fired.
Hope this makes sense,