>>73Why are you even asking if you have already made up your mind?
>>75You can put the closure on the observer list and call it directly instead of calling a notify method on it (because there's no need & closures don't usually have methods.)
Or you can skip this nonsense and embed the closure in the event classifier with a setter. Default lamdbas (or checked None instances) exist in the classifer as no-ops. Finally, instead of internal event classification, direct handling of events should be used whenever possible.