title: How to apply elevation in bottom navigation bar in flutter?
body: <p>I want to apply elevation in the bottom navigation bar. I tried elevation property but it doesn't work. Elevation property has a very negligible shadow effect. But according to my design I want higher elevation. </p>
  
  <p><strong>I want the following output...</strong></p>
  
  <p><a href="https://i.stack.imgur.com/cVr3n.png" rel="noreferrer"><img src="https://i.stack.imgur.com/cVr3n.png" alt="Desired output Image"></a>'</p>
  
  <pre class="lang-dart prettyprint-override"><code>import 'package:flutter/material.dart';
  
  class HomePage extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        body: Center(
          child: Text('Sample App'),
        ),
        bottomNavigationBar: BottomNavigationBar(
          elevation: 10,
          items: [
            BottomNavigationBarItem(
              icon: Icon(Icons.ac_unit),
                title: Text('Test')
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.access_alarm),
                title: Text('Test')
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.access_alarm),
              title: Text('Test'),
            ),
          ],
        ),
      );
    }
  }
  </code></pre>