protected override void OnIncomingMessage(byte[] identity, NetMQMessage message)
            {
                byte[] data = message.Pop().ToByteArray();

                if (data.Length > 0 && (data[0] == 1 || data[0] == 0))
                {
                    if (data[0] == 0)
                    {
                        m_subscriptions.Remove(data, 1, identity);
                    }
                    else
                    {
                        m_subscriptions.Add(data, 1, identity);
                    }
                }
            }