title: How could ViewWillDisappear be called without ViewDidDisappear in Swift
body: <p>I'm currently studying App Development with Swift course and the authors stated, that it's possible to call ViewWillDisappear(<em>:) without a corresponding call of ViewDidDisappear(</em>:), but given no example or explanation. </p>
  
  <p>I am either misunderstanding the purpose of those methods or just having a lack of experience and imagination to come with a good example on my own (I tried to make a print statement after every View LifeCycle event and testing app in that mode, but still found only "paired" statements). Thanks in advance.</p>