title: Change the flow layout of a UICollectionView
body: <p>Based on filter results, I need to change the flow layout of a collection view and reload the data using a different kind of cell. However you can't just do this:</p>
  
  <pre><code>myCollectionView.flowLayout = ...
  </code></pre>
  
  <p>So how is it possible to change the flow layout of a collection view?</p>