b2-acharcode.dart

    Future<void> main() async {
      /// Create a `CounterBloc` instance.
      final bloc = CounterBloc();

      /// Access the state of the `bloc` via `state`.
      print(bloc.state); // 0

      /// Interact with the `bloc` to trigger `state` changes.
      bloc.add(Increment());

      /// Wait for next iteration of the event-loop
      /// to ensure event has been processed.
      await Future.delayed(Duration.zero);

      /// Access the new `state`.
      print(bloc.state); // 1

      /// Close the `bloc` when it is no longer needed.
      await bloc.close();
    }