System.Net.Sockets.SocketAsyncEventArgs.FinishOperationReceiveMessageFrom C# (CSharp) Method

        private unsafe void FinishOperationReceiveMessageFrom()
        {
            IPAddress address = null;
            Interop.Winsock.WSAMsg* PtrMessage = (Interop.Winsock.WSAMsg*)Marshal.UnsafeAddrOfPinnedArrayElement(_wsaMessageBuffer, 0);

            if (_controlBuffer.Length == s_controlDataSize)
            {
                // IPv4.
                Interop.Winsock.ControlData controlData = Marshal.PtrToStructure<Interop.Winsock.ControlData>(PtrMessage->controlBuffer.Pointer);
                if (controlData.length != UIntPtr.Zero)
                {
                    address = new IPAddress((long)controlData.address);
                }
                _receiveMessageFromPacketInfo = new IPPacketInformation(((address != null) ? address : IPAddress.None), (int)controlData.index);
            }
            else if (_controlBuffer.Length == s_controlDataIPv6Size)
            {
                // IPv6.
                Interop.Winsock.ControlDataIPv6 controlData = Marshal.PtrToStructure<Interop.Winsock.ControlDataIPv6>(PtrMessage->controlBuffer.Pointer);
                if (controlData.length != UIntPtr.Zero)
                {
                    address = new IPAddress(controlData.address);
                }
                _receiveMessageFromPacketInfo = new IPPacketInformation(((address != null) ? address : IPAddress.IPv6None), (int)controlData.index);
            }
            else
            {
                // Other.
                _receiveMessageFromPacketInfo = new IPPacketInformation();
            }
        }