System.Net.Sockets.UdpClient.BeginSend C# (CSharp) Method

        public IAsyncResult BeginSend(byte[] datagram, int bytes, IPEndPoint endPoint, AsyncCallback requestCallback, object state)
        {
            // Validate input parameters.
            if (_cleanedUp)
            {
                throw new ObjectDisposedException(this.GetType().FullName);
            }
            if (datagram == null)
            {
                throw new ArgumentNullException(nameof(datagram));
            }

            if (bytes > datagram.Length || bytes < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(bytes));
            }

            if (_active && endPoint != null)
            {
                // Do not allow sending packets to arbitrary host when connected.
                throw new InvalidOperationException(SR.net_udpconnected);
            }

            if (endPoint == null)
            {
                return _clientSocket.BeginSend(datagram, 0, bytes, SocketFlags.None, requestCallback, state);
            }

            CheckForBroadcast(endPoint.Address);

            return _clientSocket.BeginSendTo(datagram, 0, bytes, SocketFlags.None, endPoint, requestCallback, state);
        }

        public ServerContext(int port, int maxclients, ref List<string> TextStack, string OwnIP)
        {
            BeginSendUdpServerCallback = new AsyncCallback(OnBeginSendUdpServerCallbackFinished);
            ServerMessage = System.Text.Encoding.ASCII.GetBytes("OK:" + OwnIP);

            UdpServer = new UdpClient(new IPEndPoint(IPAddress.Any, 8011)); //da bei xp fehler

            UdpServer.JoinMulticastGroup(BroadcastServer.Address);

            UdpServer.BeginSend(ServerMessage, ServerMessage.Length, BroadcastServer, BeginSendUdpServerCallback, null);

            MaxClients = maxclients;

            Ip = IPAddress.Any;
            this.Port = port;

            listener = new TcpListener(Ip, Port);
            Clients = new List<ClientContext>(MaxClients);

            listener.Start();

            BeginAcceptSocketCallback = new AsyncCallback(OnClientConnected);

            this.TextStack = TextStack;
        }