title: What's exactly viewDidLayoutSubviews?
body: <p>I was reading the description of <code>viewDidLayoutSubviews</code> of <code>UIViewController</code>:</p>
  
  <blockquote>
    <p>Called to notify the view controller that its view has just laid out its subviews [...] However, this method being called does not indicate that the individual layouts of the view's subviews have been adjusted. Each subview is responsible for adjusting its own layout [...].</p>
  </blockquote>
  
  <p>For me, it means: "Called when the layout of subviews is complete, but actually this is not true". So what's really behind <code>viewDidLayoutSubviews</code>?</p>