Event Reactor

Event Reactor is an object which usually produces one or more events in response to an incoming event. Unlike Event Subscriber, which always consumes events, a reacting object generates events in response to changes in the domain.

Though in some cases, Event Reactor may ignore the event, returning Nothing. It usually happens when a tuple is declared in the return type of a method, and Nothing is one possible option. For example, there could be a return type declared like EitherOf2<TaskReAssigned, Nothing>.