title: How do I make the NSUserNotification timeout?
body: <p>I am using this method: </p>
  
  <pre><code>NSUserNotification *notification = [[NSUserNotification alloc] init];
              notification.title = @"Title";
              notification.informativeText = @"body";
              notification.soundName = NSUserNotificationDefaultSoundName;
  
              [[NSUserNotificationCenter defaultUserNotificationCenter] deliverNotification:notification];
  </code></pre>
  
  <p>How can I make it timeout after 3 seconds?</p>