System.Net.Sockets.Socket.BeginConnect C# (CSharp) Method

        public IAsyncResult BeginConnect(EndPoint remoteEP, AsyncCallback callback, object state)
        {
            // Validate input parameters.
            if (NetEventSource.IsEnabled) NetEventSource.Enter(this, remoteEP);
            if (CleanedUp)
            {
                throw new ObjectDisposedException(this.GetType().FullName);
            }

            if (remoteEP == null)
            {
                throw new ArgumentNullException(nameof(remoteEP));
            }

            if (_isListening)
            {
                throw new InvalidOperationException(SR.net_sockets_mustnotlisten);
            }

            DnsEndPoint dnsEP = remoteEP as DnsEndPoint;
            if (dnsEP != null)
            {
                if (dnsEP.AddressFamily != AddressFamily.Unspecified && !CanTryAddressFamily(dnsEP.AddressFamily))
                {
                    throw new NotSupportedException(SR.net_invalidversion);
                }

                return BeginConnect(dnsEP.Host, dnsEP.Port, callback, state);
            }

            return UnsafeBeginConnect(remoteEP, callback, state, flowContext:true);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            System.Diagnostics.Stopwatch watch = new System.Diagnostics.Stopwatch();
            var ControllerIPAddress = new IPAddress(new byte[] { 192, 168, 0, 2 });
            var ControllerPort = 40001;
            var ControllerEndPoint = new IPEndPoint(ControllerIPAddress, ControllerPort);
            _client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            var header = "@";
            var command = "00C";
            var checksum = "E3";
            var end = "\r\n";
            var data = header + command + checksum + end;
            byte[] bytes = new byte[1024];

            //Start Connect
            _connectDone.Reset();
            watch.Start();
            _client.BeginConnect(ControllerIPAddress, ControllerPort, new AsyncCallback(ConnectCallback), _client);
            //wait 2s
            _connectDone.WaitOne(2000, false);

            var text = (_client.Connected) ? "ok" : "ng";
            richTextBox1.AppendText(text + "\r\n");
            watch.Stop();
            richTextBox1.AppendText("Consumer time: " + watch.ElapsedMilliseconds + "\r\n");
        }