public MasterQueryHandler(IPEndPoint master_addr, MasterQueryCompleted callback)
        {
            _callback    = callback;
            _master_addr = master_addr;

            _thread = new Thread(new ThreadStart(Run));
            _thread.IsBackground = true;
            _thread.Start();
        }
        public MasterQueryHandler(IPEndPoint master_addr, MasterQueryCompleted callback)
        {
            _callback = callback;
            _master_addr = master_addr;

            _thread = new Thread(new ThreadStart(Run));
            _thread.IsBackground = true;
            _thread.Start();
        }