如何构造UDP数据包但不发送

var udpPacketBytes = UDPPacket.Construct(IPAddress.Parse(\"1.1.1.1\"), 1000, IPAddress.Parse(\"2.2.2.2\"), 6100, payloadBytes);

public static class UDPPacket
    {
        public static byte[] Construct(IPAddress sourceAddress, ushort sourcePort, IPAddress destinationAddress, ushort destinationPort, byte[] payload)
        {
            var bindAddress = IPAddress.Any;

            // Make sure parameters are consistent
            //if ((sourceAddress.AddressFamily != destinationAddress.AddressFamily) || (sourceAddress.AddressFamily != bindAddress.AddressFamily))
            //{
            //    throw new Exception(\"Source and destination address families don\'t match!\");
            //}

            // Start building the headers
            byte[] builtPacket;
            UdpHeader udpPacket = new UdpHeader();
            ArrayList headerList = new ArrayList();
            //Socket rawSocket = null;
            //SocketOptionLevel socketLevel = SocketOptionLevel.IP;

            // Fill out the UDP header first
            Console.WriteLine(\"Filling out the UDP header...\");
            udpPacket.SourcePort = sourcePort;
            udpPacket.DestinationPort = destinationPort;
            udpPacket.Length = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
            udpPacket.Checksum = 0;

            if (sourceAddress.AddressFamily == AddressFamily.InterNetwork)
            {
                Ipv4Header ipv4Packet = new Ipv4Header();

                // Build the IPv4 header
                Console.WriteLine(\"Building the IPv4 header...\");
                ipv4Packet.Version = 4;
                ipv4Packet.Protocol = (byte)ProtocolType.Udp;
                ipv4Packet.Ttl = 2;
                ipv4Packet.Offset = 0;
                ipv4Packet.Length = (byte)Ipv4Header.Ipv4HeaderLength;
                ipv4Packet.TotalLength = (ushort)System.Convert.ToUInt16(Ipv4Header.Ipv4HeaderLength + UdpHeader.UdpHeaderLength + payload.Length);
                ipv4Packet.SourceAddress = sourceAddress;
                ipv4Packet.DestinationAddress = destinationAddress;

                // Set the IPv4 header in the UDP header since it is required to calculate the
                //    pseudo header checksum
                Console.WriteLine(\"Setting the IPv4 header for pseudo header checksum...\");
                udpPacket.ipv4PacketHeader = ipv4Packet;

                // Add IPv4 header to list of headers -- headers should be added in th order
                //    they appear in the packet (i.e. IP first then UDP)
                Console.WriteLine(\"Adding the IPv4 header to the list of header, encapsulating packet...\");
                headerList.Add(ipv4Packet);
                //socketLevel = SocketOptionLevel.IP;
            }
            else if (sourceAddress.AddressFamily == AddressFamily.InterNetworkV6)
            {
                Ipv6Header ipv6Packet = new Ipv6Header();

                // Build the IPv6 header
                Console.WriteLine(\"Building the IPv6 header...\");
                ipv6Packet.Version = 6;
                ipv6Packet.TrafficClass = 1;
                ipv6Packet.Flow = 2;
                ipv6Packet.HopLimit = 2;
                ipv6Packet.NextHeader = (byte)ProtocolType.Udp;
                ipv6Packet.PayloadLength = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
                ipv6Packet.SourceAddress = sourceAddress;
                ipv6Packet.DestinationAddress = destinationAddress;

                // Set the IPv6 header in the UDP header since it is required to calculate the
                //    pseudo header checksum
                Console.WriteLine(\"Setting the IPv6 header for pseudo header checksum...\");
                udpPacket.ipv6PacketHeader = ipv6Packet;

                // Add the IPv6 header to the list of headers - headers should be added in the order
                //    they appear in the packet (i.e. IP first then UDP)
                Console.WriteLine(\"Adding the IPv6 header to the list of header, encapsulating packet...\");
                headerList.Add(ipv6Packet);
                //socketLevel = SocketOptionLevel.IPv6;
            }

            // Add the UDP header to list of headers after the IP header has been added
            Console.WriteLine(\"Adding the UDP header to the list of header, after IP header...\");
            headerList.Add(udpPacket);

            // Convert the header classes into the binary on-the-wire representation
            Console.WriteLine(\"Converting the header classes into the binary...\");
            builtPacket = udpPacket.BuildPacket(headerList, payload);

            /*
            // Create the raw socket for this packet
            Console.WriteLine(\"Creating the raw socket using Socket()...\");
            rawSocket = new Socket(sourceAddress.AddressFamily, SocketType.Raw, ProtocolType.Udp);

            // Bind the socket to the interface specified
            Console.WriteLine(\"Binding the socket to the specified interface using Bind()...\");
            rawSocket.Bind(new IPEndPoint(bindAddress, 0));

            // Set the HeaderIncluded option since we include the IP header
            Console.WriteLine(\"Setting the HeaderIncluded option for IP header...\");
            rawSocket.SetSocketOption(socketLevel, SocketOptionName.HeaderIncluded, 1);

            try
            {
                // Send the packet!
                Console.WriteLine(\"Sending the packet...\");
                int rc = rawSocket.SendTo(builtPacket, new IPEndPoint(destinationAddress, destinationPort));
                Console.WriteLine(\"send {0} bytes to {1}\", rc, destinationAddress.ToString());
            }
            catch (SocketException err)
            {
                Console.WriteLine(\"Socket error occurred: {0}\", err.Message);
                // http://msdn.microsoft.com/en-us/library/ms740668.aspx
            }
            finally
            {
                // Close the socket
                Console.WriteLine(\"Closing the socket...\");
                rawSocket.Close();
            }
            */

            return builtPacket;
        }
    }

bits             0 – 15                   16 – 31
        +-----------------------+-------------------------+
0       | Source Port Number    | Destination Port Number |
        +-----------------------+-------------------------+
32      | Length                | Checksum                |
        +-----------------------+-------------------------+
64      |                                                 |
        |                      Data                       |
        |                                                 |
        +-------------------------------------------------+