title: Hide NSUserNotification after certain time
body: <p>Currently when i create a NSUserNotification using Alert style it won't hide unless i manually close it.</p>
  
  <p><a href="https://i.stack.imgur.com/oRDRj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/oRDRj.png" alt="enter image description here"></a></p>
  
  <p>Is there a way i can auto close/hide it say after 2 sec? </p>
  
  <p>NSUserNotification code is for reference :</p>
  
  <pre><code>let notification:NSUserNotification = NSUserNotification()
  notification.title = "Title"
  notification.subtitle = "Subtitle"
  notification.informativeText = "Informative text"
  
  notification.soundName = NSUserNotificationDefaultSoundName
  
  notification.deliveryDate = NSDate(timeIntervalSinceNow: 10)
  notification.hasActionButton = false
  let notificationcenter:NSUserNotificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter()
  notificationcenter.scheduleNotification(notification)
  </code></pre>