title: How to Move Timer to Background Thread
body: <p>I currently have two NSTimer timers in my app that are responsible for taking data and updating the UI. I have noticed recently that while the timers are running I have poor UI performance, for example the user can't scroll through my UITableview well or at all. I've read elsewhere that it is possible to push the timers into a different runloop and that this could help. This is what my timer looks like now:</p>
  
  <pre><code>let aSelector : Selector = "updateLocation"
  timer = NSTimer.scheduledTimerWithTimeInterval(((NSUserDefaults.standardUserDefaults().stringForKey("mapUpdate")! as NSString).doubleValue), target: self, selector: aSelector, userInfo: nil, repeats: true)
  </code></pre>
  
  <p>How can I modify my Swift timer such that it runs in a background thread? I've been reading about it but have been getting confused.</p>