title: If an object offers to set a delegate object - do i have to set one?
body: <p>Many Cocoa classes offer to set delegates. Now my rather simple question is: Do I have to set a delegate in this case, or is it optional to set a delegate?</p>
  
  <p>For example i use <code>NSSharingService</code>.<br>
  It comes with a <code>delegate</code> property and if i would set one, i could implement the <strong>NSSharingServiceDelegate Protocol</strong> on this delegate.
  If i am not interested in any of the methods in this protocol to be called, do I still have to set the delegate and implement these methods (as empty methods)?<br>
  Or is it an option to just not set a delegate?</p>