Type Definition extfsm::EntryExitTransitionFn

pub type EntryExitTransitionFn<ExtendedState, EventType, StateType, TransitionFnArguments, ErrorType> = dyn Fn(RefMut<'_, Box<ExtendedState>>, Option<StateType>, Option<EventType>) -> TransitionResult<EventType, StateType, TransitionFnArguments, ErrorType>;

transition function to either enter or exit a specific state, return same as FSMTransitionFn. StateType passed in is previous state before currently entered or exited state. EventType is indicating which event causes the enter or exit. This allows to track where an FSM entered or exited a state from which can be of high interest in “stable” states of the FSM. In case of Entry on the first state it may be all None.