TCP非同期プログラミング受信データ問題

private static void Receive(Socket client)
        {
            try
            {
                // Create the state object.     
                StateObject state = new StateObject();
                state.workSocket = client;
                // Begin receiving the data from the remote device.     
                client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);
            }
            catch (Exception e)
            {
                MessageBox.Show("Receive " + e.ToString());
            }
        }
        private static void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                // Retrieve the state object and the client socket     
                // from the asynchronous state object.     
                StateObject state = (StateObject)ar.AsyncState;
                Socket client = state.workSocket;
                // Read data from the remote device.     
                int bytesRead = client.EndReceive(ar);
                if (bytesRead > 0)
                {
                    // There might be more data, so store the data received so far.     
                    string getMsg = Encoding.ASCII.GetString(state.buffer, 0, bytesRead);

                    //Console.WriteLine(" " + getMsg + " ");
                    MessageBox.Show(" " + getMsg);
                    state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));

                    // Get the rest of the data.     
                    client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);

                }
                else
                {
                    // All the data has arrived; put it in response.     
                    if (state.sb.Length > 1)
                    {
                        response = state.sb.ToString();
                    }
                    // Signal that all bytes have been received.     
                    receiveDone.Set();
                }
            }
            catch (Exception e)
            {
                MessageBox.Show("Receive " + e.ToString());
            }
        }