title: UIViewControllerAnimatedTransitioning with Safe Area Insets on iPhone X
body: <p>When <code>animateTransition</code> is called on the transitioning delegate the Safe Area Insets have yet to be set on the 'to view controller'. </p>
  
  <p>I've tried forcing a layout by calling: <code>toViewController.view.setNeedsLayout()</code> and <code>toViewController.view.layoutIfNeeded()</code> without success. </p>
  
  <p>Can anyone suggest a means of either forcing the Safe Area Insets to be set early or determining how I should know the insets in time for the transition to work as it ought. </p>
  
  <p>The effect is that I have a <code>UICollectionViewCell</code> that appears to move down once the transition completes. This is due to the frame having a <code>0,0</code> origin initially rather than say <code>0,44</code> on the iPhone X which it has eventually once the Safe Area Insets are set, by which time the transition will have completed.</p>