   public static let LinkCountChange  = SKQueueNotification(rawValue: UInt32(NOTE_LINK))
   public static let AccessRevocation = SKQueueNotification(rawValue: UInt32(NOTE_REVOKE))
   public static let Unlock           = SKQueueNotification(rawValue: UInt32(NOTE_FUNLOCK))
+  public static let DataAvailable    = SKQueueNotification(rawValue: UInt32(NOTE_NONE))
   public static let Default          = SKQueueNotification(rawValue: UInt32(INT_MAX))
 
   public func toStrings() -> [SKQueueNotificationString] {

    if contains(.LinkCountChange)  { s.append(.LinkCountChange) }
    if contains(.AccessRevocation) { s.append(.AccessRevocation) }
    if contains(.Unlock)           { s.append(.Unlock) }
    return s
  }
}

  case LinkCountChange
  case AccessRevocation
  case Unlock
  case DataAvailable
}

public struct SKQueueNotification: OptionSet {
