title: Flutter setEnabledSystemUIOverlays hide top statusbar
body: <p>I encountered a problem when I set the SystemUiOverlay.bottom on my appbarwidget using <code>SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom])</code> and noticed that status bar is hidden but once I pull down upper side of the screen it shows and doesn't disappear again. So I came up with the idea to add a gesture detector for the whole widget app to hide it all the time when you press anywhere on the screen. And I am wondering if this is the best solution and there will not be any issues with the performance or whatever. Any thoughts?</p>
  
  <pre><code>void main() =&gt; runApp(PlanetsApp());
  
  class PlanetsApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return new GestureDetector(
        onTap: () =&gt; SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom]),
        child: new MaterialApp(
          debugShowCheckedModeBanner: false,
          title: 'Planets App',
          color: Colors.purple,
          home: HomeScreen(),
        ),
      );
    }
  }
  </code></pre>