title: AutomaticKeepAliveClientMixin not working with a BottomNavigationBar Page
body: <p>I'm trying to keep only one page alive, but it doesn't work. I have all the required stuff.</p>
  <ul>
  <li>added the <code>with AutomaticKeepAliveClientMixin&lt;PageName&gt;</code></li>
  <li>added the <code> @override bool get wantKeepAlive =&gt; true;</code> at the end</li>
  <li>added the <code>super.build(context);</code> inside the build</li>
  </ul>
  <blockquote>
  </blockquote>
  <p>Here's the code of the Page with the AutomaticKeepAliveClientMixin:</p>
  <pre><code>class MatchingPage extends StatefulWidget {
    //
    static final id = 'match';
    //
    @override
    _MatchingPageState createState() =&gt; _MatchingPageState();
  }
  
  class _MatchingPageState extends State&lt;MatchingPage&gt; with AutomaticKeepAliveClientMixin&lt;MatchingPage&gt; {
  
    @override
      void initState() {
        super.initState();
        print('MATCHING PAGE');
        print(User.uid);
      }
  
    @override
    Widget build(BuildContext context) {
      super.build(context);
      setState(() {
        screenHeight = MediaQuery.of(context).size.height;
        screenWidth = MediaQuery.of(context).size.width;
      });
      return ModalProgressHUD(
        inAsyncCall: showSpinner,
        child: AnnotatedRegion&lt;SystemUiOverlayStyle&gt;(
          value: SystemUiOverlayStyle(
            statusBarColor: Colors.white.withOpacity(0.10), 
            statusBarIconBrightness: Brightness.dark),
          child: Scaffold(
            backgroundColor: Colors.white,
            body: SafeArea(
              child: Text('MatchPage'),
            ),
          ),
        ),
      );
    }
  
    @override
    bool get wantKeepAlive =&gt; true;
  }
  </code></pre>
  <blockquote>
  </blockquote>
  <p>And here's the code of the Page that has the BottomNavBar:</p>
  <pre><code>List&lt;Widget&gt; _pages = [ProfilePage(), MatchingPage(), ChatsPage()];
  
  class HomePage extends StatefulWidget {
    //
    static String id = 'home';
    //
    @override
    _HomePageState createState() =&gt; _HomePageState();
  }
  
  class _HomePageState extends State&lt;HomePage&gt; {
    //
    int pageIndex = 1;
    //
  
    @override
    Widget build(BuildContext context) {
      return CustomScaffoldWithNavBar(
        statusBarColor: Colors.white,
        statusBarIconBrightness: Brightness.dark,
        backgroundColor: Colors.white,
        bottomNavigationBar: BottomNavigationBar(
          backgroundColor: Colors.white,
          currentIndex: pageIndex,
          selectedItemColor: Colors.balck,
          unselectedItemColor: _kAppIconGray,
          type: BottomNavigationBarType.fixed,
          showSelectedLabels: false,
          showUnselectedLabels: false,
          items: [
            BottomNavigationBarItem(icon: Icon(...), title: Text('')),
            BottomNavigationBarItem(icon: Icon(...), title: Text('')),
            BottomNavigationBarItem(icon: Icon(...), title: Text('')),
          ],
          onTap: (int index) {
            setState(() =&gt; pageIndex = index);
          },
        ),
        child: _pages[pageIndex],
      );
    }
  }
  </code></pre>