https://wiki.unrealengine.com/Event_handling
The goal for this wiki is to be a goto page for learning a general method for writing event handlers to interface with a target delegate, to give a top-down view of this part of the engine and pass on a grasp of the idioms required to handle events via C++. Why is understanding delegates important? Events are handled by delegates. The delegate "system: is a key vertebrae in the backbone of the UDK’s messaging system, the idioms and axioms surrounding the defining of delegates will be essential learning for anyone doing non-trivial work with the engine on it’s higher levels.
Should include the usage of the returned handle from delegates and should probably also explain the difference between dynamic (blueprint) and regular (c++) delegates.