title: What is the default animation duration for UICollectionView layout changes?
body: <p>Say I do this:</p>
  
  <pre><code>[self.collectionView setCollectionViewLayout:myNewLayout animated:YES];
  </code></pre>
  
  <p>What is the duration of the animation that happens?</p>
  
  <p>My application of this is that I'm animating layer properties inside the cells when this changes, and because layer animations don't get caught by <code>UIView</code>'s block-based animations, I have to do it separately with my own animation block.</p>