onTransition method
Called whenever a transition occurs in any bloc with the given bloc
and transition.
A transition occurs when a new event is added
and a new state is emitted from a corresponding EventHandler.
onTransition is called before a bloc's state has been updated.
Implementation
@override
// ignore: unnecessary_overrides
void onTransition(Bloc bloc, Transition transition) {
super.onTransition(bloc, transition);
// log('bloc: $bloc .. transition: $transition');
}