title: Class extension vs. subclassing in Swift?
body: <p>I'am using a third-party framework that provides a class whose instances only have properties. In my app, I'd like to add an extra property to this instances. What the appropriate way to do this would it be for this scenario?</p>
  
  <p>a) Extending the framework's class in my app</p>
  
  <p>b) Creating a subclass of the framework's class and define the new property I need</p>
  
  <p>Thanks in advance  </p>