title: Navigate part of screen from drawer
body: <p>let's say I have an app with the following setup:</p>
  <pre><code>  @override
    Widget build(BuildContext context) {
      return Scaffold(
          appBar: AppBar(),
          body: Container(
            color: Colors.grey[200],
            child: Row(
              children: [
                MainMenu(),
                Expanded(child: MainLoginScreen()),
              ],
            ),
          ));
    }
  }
  </code></pre>
  <p>I would like to know how can I navigate only the MainLoginScreen widget from the MainMenu with any .push() method.</p>
  <p>(I found a way to navigate from a context inside the mainloginscreen,by wrapping it with a MaterialApp widget, but what if I want to use the MainMenu widget instead, which has another context)</p>