在BLoC类中使用EquatableMixin，并确保在调用emit()之前更新状态。示例代码如下：

import 'package:equatable/equatable.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

abstract class CounterState extends Equatable {
  final int counter;

  CounterState(this.counter);

  @override
  List