2. Modify the Echo programs to make them function as a single file download application as described in the program section below. 3. Demonstrate the program in the lab. The Program Implement a file transfer service as shown in the following figure: Client TCP/IP Server socket socket bind connect listen write filename accept read read write file close In this service, it is the client that initiates the TCP connection with the server. After the connection was established, the client sends the name of the file it wants to download from the server. The server will try to open the requested file. If the file opening is successful, the server will send the file to the client; if it is not successful, the server will send back an error message. The server will close the TCP connection once the file is completely sent. The closing of the TCP connection is used to indicate the end of the file download. You may implement the service by modifying the echo client and server programs.