title: Fixed header with CoordinatorLayout showing shadow when scrolling
body: <p>The classic coordinator layout gives you the following <a href="http://saulmm.github.io/mastering-coordinator" rel="nofollow noreferrer">[source]</a>:
  <a href="https://web.archive.org/web/20171019042325/http://androcode.es/wp-content/uploads/2015/10/simple_coordinator.gif" rel="nofollow noreferrer"><img src="https://web.archive.org/web/20171019042325/http://androcode.es/wp-content/uploads/2015/10/simple_coordinator.gif" alt="coordinator layout" /></a></p>
  <p>However, I don't want the top header views to scroll until they &quot;become&quot; a toolbar pinned at the top, with a shadow below. I want them all fixed (or pinned) but to show the shadow only the nested scroll view starts to scroll under the pinned ones. Something like the main app drawer on Marshmallow devices, where the &quot;search bar&quot; becomes pinned and the list of apps scroll under it.</p>
  <p>Hope I made myself clear. Is there any easy way I could achieve that without listening for scroll events and handling this manually?</p>
  <p><strong>EDIT</strong></p>
  <p>Here is what I'm trying to achieve:</p>
  <p><img src="https://phandroid.s3.amazonaws.com/wp-content/uploads/2015/05/Android-M-app-drawer.jpg" alt="App drawer" />. Notice on the right image how there is now a shadow below the list of apps because the user scrolled the list.</p>
  <p>Thank you!</p>