title: How to pause the sound when use SpriteKit
body: <p>I want to use <code>SpriteKit</code> to play sound, the question is that I use the function:</p>
  
  <pre><code>[SKAction playSoundFileNamed:@"sound.wav" waitForCompletion:NO];
  </code></pre>
  
  <p>But when I want to pause the game, the sound is still play.</p>
  
  <p>How to stop the sound when <code>skview.pause</code> is set to <code>YES</code>, and to resume the sound when <code>skview.pause</code> is set to <code>NO</code>?</p>