title: Gradient background on FloatingActionButton in Flutter
body: <p>Is it possible to set backgroundColor of FAB to gradient instead of plain color?</p>
  
  <p>My button:</p>
  
  <pre><code>floatingActionButton: FloatingActionButton(
      backgroundColor: const Color(0xFFFF006E),
      child: const Icon(Icons.add, size: 40.0),
      onPressed: () {
          print('Start');
      },
  ),
  </code></pre>