title: Shadows slow up UIScrollView
body: <p>I have a <code>UIScrollView</code> that pretty much functions like a Facebook <strong>news feed</strong>. I thought my elements were slowing the scroll fps down. By process of elimination, I found out that the <strong>shadows slow down</strong> my app.</p>
  
  <p>The <code>UIView</code> boxes inside the scroll view have such configuration:</p>
  
  <pre><code>self.layer.shadowColor = UIColor.blackColor().CGColor
  self.layer.shadowOffset = CGSizeMake(0, 2)
  self.layer.shadowRadius = 2
  self.layer.shadowOpacity = 0.15
  </code></pre>
  
  <p>Like a news feed, my scroll view has many boxes, therefore having <code>UIView</code>s with their own shadows. How do I go with this without slowing down my app?</p>