title: calling dequeueReusableCellWithReuseIdentifier forIndexPath causes infinite loop
body: <p>I can't arbitrarily dequeue cells for calculating heights like I could with <code>UITableView</code>. What would be the equivalent way of doing this with a <code>UICollectionView</code>?</p>
  
  <p><code>dequeueResuableCellWithReuseIdentifier:forIndexPath</code> is calling <code>sizeForItemAtIndexPath</code>. Which in return is calling <code>dequeueResuableCellWithReuseIdentifier:forIndexPath</code> etc..</p>
  
  <p>I call <code>dequeueResuableCellWithReuseIdentifier:forIndexPath</code> in <code>sizeForItemAtIndexPath</code> to be able to retrieve the height of the cells. I have many different cell sizes in my storyboard.</p>