didStartListening method Null safety

  1. @override
void didStartListening()
override

Called when the number of listeners changes from zero to one.

Implementation

@override
void didStartListening() {
  first.addListener(_maybeNotifyListeners);
  first.addStatusListener(_maybeNotifyStatusListeners);
  next.addListener(_maybeNotifyListeners);
  next.addStatusListener(_maybeNotifyStatusListeners);
}