private void OnMessageSent(CallbackArgs response)
 {
     Dispatcher.BeginInvoke((Action)(() => { trace.Add(response); }));
 }
 protected void OnNotified(NotificationType notificationType, HttpWebResponse response, SendNotificationToMPNSCompleted callback)
 {
     CallbackArgs args = new CallbackArgs(notificationType, response);
     if (null != callback)
         callback(args);
 }