title: iOS: can I use one timer to trigger multiple things at certain times?
body: <p>I need a button to do different things depending on how far along the person is in watching a video. </p>
  
  <p>So for instance at 0-20 seconds it does thing A
  then at 20-25 it does thing B
  and 25-32 thing C</p>
  
  <p>Can I make a timer that counts up and fires different messages off at specific intervals to enable/disable my buttons or change what they do?</p>
  
  <p>Or should I have it fire and simultaneously start another timer and change what my button does and form a chain of events?</p>
  
  <p>Thanks!</p>