Every fundamental ActiveJS construct has a number of built-in Observable events. You can listen to these events by subscribing to the events$ Observable, a property of every fundamental construct.
Units, Systems, Action, and Cluster have a common EventReplay event, it is triggered on a successful manual replay when you call the replay() method.
Units have many Units specific events that let you tap into all the action that's happening on a Unit.
Every Unit has some common events like EventUnitDispatch, EventUnitDispatchFail andEventUnitFreeze etc.
ListUnit and DictUnit have even more events specific to them, like EventDictUnitSet, EventListUnitPush or EventListUnitPop etc.