private void TearDownPubSub()
 {
     if (Publisher != null)
     {
         Publisher.StopListening();
     }
     if (Subscriber != null)
     {
         Subscriber.StopListening();
     }
 }
 private void TearDownPubSub()
 {
     Publisher?.StopListening();
     Subscriber?.StopListening();
 }