Opc.Ua.Bindings.TcpMessageSocket.DoReadComplete C# (CSharp) Method

        private ServiceResult DoReadComplete(SocketAsyncEventArgs e)
        {
            // complete operation.
            int bytesRead = e.BytesTransferred; 
            
            lock (m_socketLock)
            {
                BufferManager.UnlockBuffer(m_receiveBuffer);
            }
             
            if (bytesRead == 0)
            {
                // free the empty receive buffer.
                if (m_receiveBuffer != null)
                {
                    m_bufferManager.ReturnBuffer(m_receiveBuffer, "DoReadComplete");
                    m_receiveBuffer = null;
                }

                return ServiceResult.Good;
            }

            // Utils.Trace("Bytes read: {0}", bytesRead);

            m_bytesReceived += bytesRead;

            // check if more data left to read.
            if (m_bytesReceived < m_bytesToReceive)
            {
                ReadNextBlock();
                
                return ServiceResult.Good;
            }

            // start reading the message body.
            if (m_incomingMessageSize < 0)
            {
                m_incomingMessageSize = BitConverter.ToInt32(m_receiveBuffer, 4);

                if (m_incomingMessageSize <= 0 || m_incomingMessageSize > m_receiveBufferSize)
                {
                    Utils.Trace(
                        "BadTcpMessageTooLarge: BufferSize={0}; MessageSize={1}", 
                        m_receiveBufferSize, 
                        m_incomingMessageSize);

                    return ServiceResult.Create(
                        StatusCodes.BadTcpMessageTooLarge, 
                        "Messages size {1} bytes is too large for buffer of size {0}.", 
                        m_receiveBufferSize,
                        m_incomingMessageSize);
                }

                // set up buffer for reading the message body.
                m_bytesToReceive = m_incomingMessageSize;
                
                ReadNextBlock();

                return ServiceResult.Good;
            }
            
            // notify the sink.
            if (m_sink != null)
            {
                try
                {
                    // send notification (implementor responsible for freeing buffer) on success.
                    ArraySegment<byte> messageChunk = new ArraySegment<byte>(m_receiveBuffer, 0, m_incomingMessageSize);

                    // must allocate a new buffer for the next message.
                    m_receiveBuffer = null;

                    m_sink.OnMessageReceived(this, messageChunk);
                }
                catch (Exception ex)
                {
                    Utils.Trace(ex, "Unexpected error invoking OnMessageReceived callback.");
                }
            }

            // free the receive buffer.
            if (m_receiveBuffer != null)
            {
                m_bufferManager.ReturnBuffer(m_receiveBuffer, "DoReadComplete");
                m_receiveBuffer = null;
            }

            // start receiving next message.
            ReadNextMessage();

            return ServiceResult.Good;
        }