title: Swift 3: subclassing NSObject or not?
body: <p>I have read some posts like <a href="https://stackoverflow.com/questions/24057525/swift-native-base-class-or-nsobject/">this one</a> about the difference between subclassing <code>NSObject</code> in Swift or just having its native base <code>class</code> with no subclassing. But they all are a bit old posts, and I am not clear about this topic.</p>
  
  <p>When should you subclass <code>NSObject</code>? What is the actual difference between subclassing it and not subclassing? What is currently the recommendation in Swift?</p>