title: How to pause PerformSelector from execution?
body: <p>I'm having serious problem whenever I pause the game, since most of my <code>performSelector:</code> has delay, so it will not execute immediately, but thing goes bad if I'm pausing the game then the <code>performSelector</code> is still calling... How should I overcome this?</p>
  
  <p>I know there is one function under <code>NSObject</code> to cancel all the requests but that's not really what i'm looking for because I want the method to continue execute if the player resume the game.</p>