GUI based on tkinter.
This assignment is a hasty rush, so it is for reference only. There are many areas where code needs to be improved, such as soundness, security, and modularity.
The core logic is to create a socket object, then bind the server process to a specific port, and then set the number of listeners. The server enters the LISTEN state, begins to cyclically receive the TCP connection initiated by the client, and processes each connection in a multi-threaded manner.
