struct StateTransitor(StateType, EventType, StateType defaultStateParameter = StateType.init, ProcHandler = void delegate()[], ExceptionHandler = void delegate(Exception)[], EventHandler = void delegate(EventType)[], StateChangedHandler = void delegate(StateType newSts, StateType oldSts)[], ConsumeMode consumeMode = ConsumeMode.combined, EventContainer = SList!EventType)
Set exception handler
If other handler has already been set, the other handler is no longer used and replaced by handler instead.