public void Unregister(IDataReceivedEventHandler eventHandler)
 {
     if (_dataReceivedEventHandlers != null)
     {
         _dataReceivedEventHandlers.Remove(eventHandler);
     }
 }
        public void Register(IDataReceivedEventHandler eventHandler)
        {
            if (_dataReceivedEventHandlers == null)
            {
                _dataReceivedEventHandlers = new HashSet<IDataReceivedEventHandler>();
            }

            _dataReceivedEventHandlers.Add(eventHandler);
        }