title: notifyListeners in provider not working cause use class inside provider?
body: <p>I had a Provider class &quot;Provider_Controller&quot;, when i use all method in thats class it working properly with notifyListeners,
  but when i put in class  &quot;Provider_Chat&quot; inside &quot;Provider_Controller&quot; notifyListeners not working properly event when data in &quot;Provider_Chat&quot;  be updated,</p>
  <p>i'am using provider: ^5.0.0</p>
  <pre><code>class Provider_Controller with ChangeNotifier {
      Provider_Chat _provider_chat = new Provider_Chat();
  
      Provider_Chat get provider_chat =&gt; _provider_chat;
      set provider_chat(Provider_Chat pc) {
        try {
        _provider_chat = pc;
         notifyListeners();
      } catch (err) {
        print(err);
      }
    }
    Model_User _user;
    Model_User get user =&gt; _user;
    set user(Model_User user) {
      _user = user;
      notifyListeners();
    }
  
    List&lt;Model_User_Chat_Contact&gt; _list_user_chat;
  
    List&lt;Model_User_Chat_Contact&gt; get list_user_chat =&gt; _list_user_chat;
    set list_user_chat(List&lt;Model_User_Chat_Contact&gt; new_list) {
      _list_user_chat = new_list;
      notifyListeners();
    }
  
  
  }
  
  class Provider_Chat {
    TextEditingController _textEditingController_message =
        TextEditingController();
    TextEditingController get textEditingController_message =&gt;
        _textEditingController_message;
    set textEditingController_message(TextEditingController input) {
      _textEditingController_message = input;
    }
  
    List&lt;Model_Chat&gt; _list_chat;
  
    List&lt;Model_Chat&gt; get list_chat =&gt; _list_chat;
    set list_chat(List&lt;Model_Chat&gt; new_list) {
      try {
        _list_chat = new_list;
      } catch (err) {
        print(err);
      }
    }
  }
  
  
  </code></pre>
  <p>ex:</p>
  <pre><code>Provider_Controller pc = Provider.of&lt;Provider_Controller&gt;(context); 
  </code></pre>
  <p>access method inside &quot;Provider_Controller&quot; is still working.</p>
  <pre><code>pc.user  = new_user(); // notifyListeners working fine
  </code></pre>
  <p>but when.. access</p>
  <pre><code>pc.provider_chat.list_chat = new_list(); // the data still changed, but notifyListeners not working
  </code></pre>