Cancel all pending instances of after event Event.
+Event
Atom
Description
All instances of the pending after event Event is cancelled so that the
event will not be triggered. A pending after event is an event which is
setup by either event_after/2 or event_after_every/2, and which is
waiting to be raised (event_after_every/2 will always be pending as
it is raised repeatedly).
Note that the processing of an already raised, but as yet unprocessed
event will not be cancelled by this predicate.