public void CancelSubscription(IDownStreamSubscriber subscriber)
 {
     if (subscribers.Contains(subscriber))
     {
         subscribers.Remove(subscriber);
     }
 }
 /// <summary>
 /// Alias for CancelSubscription
 /// </summary>
 /// <param name="subscriber"></param>
 public void Unsubscribe(IDownStreamSubscriber subscriber)
 {
     CancelSubscription(subscriber);
 }
 public void Subscribe(IDownStreamSubscriber subscriber)
 {
     subscribers.Add(subscriber);
 }