如何从flutter区块全局收听？

dependencies:
  flutter_bloc: ^7.0.0

import 'package:flutter_bloc/flutter_bloc.dart';

enum CounterEvent { increment, decrement }

class CounterBloc extends Bloc<CounterEvent, int> {
  CounterBloc() : super(0);

  @override
  Stream<int> mapEventToState(CounterEvent event) async* {
    switch (event) {
      case CounterEvent.increment:
        yield state + 1;
        break;
      case CounterEvent.decrement:
        yield state - 1;
        break;
    }
  }
}

BlocProvider(
  create: (context) => CounterBloc(),
  child: YourWidget(),
)

BlocBuilder<CounterBloc, int>(
  builder: (context, state) {
    return Text('Count: $state');
  },
)

BlocProvider.of<CounterBloc>(context).add(CounterEvent.increment);