title: How to update size of cells in UICollectionView after cell data is set?
body: <p>So I have a UICollectionView with a different image of different size in each cell. When cellForItemAtIndexPath: is called, I update the UICollectionViewCell with a method that fetches an image asynchronously on the web and displays it full size.</p>
  
  <p>My problem is the size of my cell is already set prior with sizeForItemAtIndexPath. I would like it to be recalled so the cell has the downloaded image size.</p>
  
  <p>How can I do this?</p>