title: Flutter - BloC Cubit function doesn't emitting state
body: <p>I'm creating a Flutter application. I'm added a BloC to my project for management state.
  I created a list with data. And I want to add item to ListView manually with button 'Add'.</p>
  <p>I'm wrote a code:</p>
  <p><strong>My Item Cubit</strong></p>
  <pre><code>class ItemCubit extends Cubit&lt;List&lt;Item&gt;&gt; {
    ItemCubit() : super([]);
  
    void addItem(item){
      state.add(item);
      emit(state);
    }
  }
  </code></pre>
  <p><strong>Page of Items with Provider</strong>:</p>
  <pre><code>class SearchPage extends StatelessWidget {
    const SearchPage({Key? key}) : super(key: key);
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        home: BlocProvider(
          create: (_) =&gt; ItemCubit(),
          child: Search(),
        ),
      );
    }
  }
  </code></pre>
  <p>And I call the BlocBuilder in Stateless Widget like this:</p>
  <pre><code>body: BlocBuilder&lt;MarketCubit, List&lt;Market&gt;&gt;(
              builder: (context, items) =&gt; TabBarView(...))
  </code></pre>
  <p>So when I call my function from state:</p>
  <pre><code>Item item = Item(1, 'Item 1');
  
  
  ElevatedButton(onPressed:(){
    context.read&lt;ItemCubit&gt;().addItem(item);
   }, child: Text('Add Item')),
  </code></pre>
  <p>The ListView doesn't updating. What's problem?
  Thanks a lot!</p>