is called when the master environment (e.g., desktop) was cancelled in
it's terminate request.
Termination can be intercepted by throwing TerminationVetoException.
But if a listener was queried for termination .. doesnt throwed a veto exception ...
it doesnt know if termination will be real next time.
Because any other listener can throw those exception too ... and so it can happen
that after queryTermination() no notifyTermination() will occure. But these listener
doesnt know if its allowed to start new processes then.
Using this optional(!) interface will make it possible to be informed about
cancelled termination requests also.
Parameter Event
describe the source of the event (e.g., the desktop)