title: Bloc Delegate : Classes can only extend other classes. Try specifying a different superclass, or removing the extends clause
body: <p><strong>I was upgrading my flutter_bloc to version:</strong></p>
  <pre><code>  flutter_bloc: ^7.0.0
  </code></pre>
  <p>from</p>
  <pre><code>  flutter_bloc: ^3.2.0
  </code></pre>
  <p>but now it seems that the BlocDelegate class doesn't seems to work and ,i am stuck on this  problem</p>
  <blockquote>
  <p>Here is my code</p>
  </blockquote>
  <pre><code>import 'package:flutter_bloc/flutter_bloc.dart';
  
  class SimpleBlocDelegate extends BlocDelegate {
  @override
  void onEvent(Bloc bloc, Object event) {
  print(event);
  super.onEvent(bloc, event);
  }
  
  @override
  void onError(Bloc bloc, Object error, StackTrace stackTrace) {
  print(error);
  super.onError(bloc, error, stackTrace);
  }
  
  @override
  void onTransition(Bloc bloc, Transition transition) {
  print(transition);
  super.onTransition(bloc, transition);
   }
  }
  </code></pre>
  <p>is there a solution to it or should i downgrade ?</p>
  <p>My flutter version :</p>
  <p>Flutter 2.2.0 • channel stable •</p>
  <p>Framework • revision b22742018b (2 weeks ago) • 2021-05-14 19:12:57 -0700</p>
  <p>Engine • revision a9d88a4d18</p>
  <p>Tools • Dart 2.13.0</p>