title: How can I change the size of drawer/back button icons of appbar without modifying the behavior provided by default in Flutter?
body: <p>I am trying to change the size of the icons ("Back" provided by Navigator and "Drawer" provided by Scaffold) in appbar in my ThemeData, modifying iconTheme and primaryIconTheme:</p>
  
  <pre><code>ThemeData(
      primarySwatch: Colors.blue,
      iconTheme: IconThemeData(color: Colors.grey, size: 32),
      primaryIconTheme: IconThemeData(color: Colors.grey, size: 32)
    ),
  </code></pre>
  
  <p>This lines only changes the color of the icons, but the size does not change.</p>
  
  <p>I do not need to change the behavior that Flutter handles this button, only the size of them.</p>