title: Instantiate a background runloop in iOS
body: <h2>Use Case</h2>
  <p>I have a set of processes that each need to run on their own background thread at a certain execution rate (3 times a second, once every 10 seconds etc).</p>
  <p>I <em>believe</em> <code>CFRunLoop</code> and/or <code>NSRunLoop</code> provide this functionality</p>
  <h2>Question</h2>
  <p>How do I create (in swift) a new background thread for which to execute a periodic tasks on?</p>