title: What events are produced by UIControl on tvOS?
body: <p>With <code>UIButton</code>, tvOS produces <code>UIControlEvents.PrimaryActionTriggered</code> (not <code>.TouchUpInside</code>, as it does on iOS) when the button gets focus and the user taps on the remote.</p>
  
  <p><code>UIControl</code>'s don't seem to produce <em>either</em> of these events, however.  I can't see that it produces any events, in fact, when the user focuses on the control and taps on the remote. </p>
  
  <p>How does one use a custom <code>UIControl</code> for tvOS?</p>