title: How do I create a UICollectionView with column and row headers?
body: <p>I want to create a UICollectionView that looks like this:</p>
  
  <p><img src="https://i.stack.imgur.com/hOGvk.jpg" alt="Yep. This."></p>
  
  <p>It won't be scrollable or editable. I'm currently wondering how to write the layout for this. I'm guessing it won't be a subclass of <code>UICollectionViewFlowLayout</code>. I can think of a number of ways, but was curious if there was any "right" way. The cells will be animate-able.</p>
  
  <p>Should each row or column be its own section?</p>