title: How to create toolbar searchview in flutter
body: <p>I need to implement <code>searchview</code> in toolbar my app to filter a list view:</p>
  <p><a href="https://i.stack.imgur.com/MH9R6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MH9R6.png" alt="" /></a></p>