title: UICollectionView custom line separators
body: <p>I wanna making <strong>2pt black separators</strong> in <code>UICollectionView</code> for our new app. Screenshot from our app is below. We couldn't use <code>UITableView</code>, because we have custom insert/delete animations, scrolling and parallax effects and so on.</p>
  
  <p><img src="https://i.stack.imgur.com/hujC3.png" alt="Example"></p>