anchor.diff:  class _HomeState extends State<Home> {
     static const TextStyle optionStyle =
         TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
  -  static final List<Widget> _widgetOptions = <Widget>[
  -    TabNavigator(
  -      navigatorKey: navigatorKeys[AppTab.profile],
  -      routes: {
  -        '/': (context) => ProfileDashboard(),
  -      },
  -    ),
  -    TabNavigator(
  -      navigatorKey: navigatorKeys[AppTab.runs],
  -      routes: {
  -        '/': (context) => UserRunsPage(),
  -        '/run-details': (context) => RunDetailsPage(),
  -      },
  -    ),
  -    TabNavigator(
  -      navigatorKey: navigatorKeys[AppTab.pastEvents],
  -      routes: {
  -        '/': (context) => PastEventsPage(),
  -        '/event-results': (context) => EventResultsPage(),
  -      },
  -    ),
  -    TabNavigator(
  -      navigatorKey: navigatorKeys[AppTab.futureEvents],
  -      routes: {
  -        '/': (context) => FutureEventsPage(),
  -      },
  -    ),
  -    TabNavigator(
  -      navigatorKey: navigatorKeys[AppTab.offlineChart],
  -      routes: {
  -        '/': (context) => OfflineChartPage(),
  -      }
  -    )
  -  ];
   
     int _selectedIndex = 0;
     TabNavigationHelper _tabHelper;
  +  List<Widget> _widgetOptions;
   
     set selectedIndex(value) {
       if (value != _selectedIndex) {
  
positive.code:   void initState() {
      super.initState();
      this._tabHelper = TabNavigationHelper(this);
    }
  
    void _onItemTapped(int index) {
  
negative.code: }
  
  class TabNavigationHelper {
    Map<AppTab, GlobalKey<NavigatorState>> navigatorKeys = {
      AppTab.profile: GlobalKey<NavigatorState>(),
      AppTab.runs: GlobalKey<NavigatorState>(),
      AppTab.futureEvents: GlobalKey<NavigatorState>(),
      AppTab.pastEvents: GlobalKey<NavigatorState>(),
      AppTab.offlineChart: GlobalKey<NavigatorState>()
    };
  
    _HomeState _home;
  
    TabNavigationHelper(this._home);
  