 
     // MARK: Internal
 
-    internal func willEnterForeground(_ notification: Notification?) {
+    @objc internal func willEnterForeground(_ notification: Notification?) {
         self.startAnimatingContentView()
     }
 


    // MARK: Timer callbacks

    internal func performDelayedHide(_ timer: Timer? = nil) {
        let userInfo = timer?.userInfo as? [String:AnyObject]
        let key = userInfo?["timerActionKey"] as? String
        var completion: TimerAction?

        hide(animated: true, completion: completion)
    }

    @objc internal func handleGraceTimer(_ timer: Timer? = nil) {
        // Show the HUD only if the task is still running
        if (graceTimer?.isValid)! {
            showContent()
