title: NSTimer stops in the background after some time
body: <p>I used NSTimer to call a method after 1 sec when app goes in background and after nearly 17 minutes timer stops working.</p>
  
  <p>When it came back in the foregound it again started working, so please tell me why this is happening and how to resolve the issue.</p>
  
  <p>I also tried using perform selector with delay in recursion for the same purpose, but again giving the same result. Please suggest any solution. Any help will be completely appreciated.</p>