         let userNotification = NSUserNotificationBuilder.build(notification)
         notifications.append(notification)
         userNotificationCenter.deliverNotification(userNotification)
+
+        timer = Timer(interval: 30.0) { [weak self] _ in
+            self?.clearAllNotifications()
+        }
     }
 }
 

extension NotificationCenter {

    func clearAllNotifications() {
        userNotificationCenter.removeAllDeliveredNotifications()
        notifications.removeAll()
    }


    private let userNotificationCenter: NSUserNotificationCenter
    private var notifications = [Notification]()
    private var timer: Timer?

    private init(userNotificationCenter: NSUserNotificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter()) {
        self.userNotificationCenter = userNotificationCenter
