title: How to change UICollectionView zIndex?
body: <p>Check the image below. I need to <strong>highlight</strong> the focused cell such that it is above all the cells in <code>collectionView</code>.<br>
  I know I have to change the <code>zIndex</code> of the focused cell. How to do that?<br>
  I need the logic. My code is in <code>objective-c</code>.</p>
  
  <p>This is for <code>tvOS</code> but <code>iOS</code> code will also work here I guess.</p>
  
  <p><a href="https://i.stack.imgur.com/DIVfz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DIVfz.png" alt="enter image description here"></a></p>