Custom read handler for sockets demo for appserver.py and appclient.py (libserver, libclient)

ℹ️
https://github.com/realpython/materials/blob/master/python-sockets-tutorial/app-server.py
https://github.com/realpython/materials/blob/master/python-sockets-tutorial/app-client.py
https://github.com/realpython/materials/blob/master/python-sockets-tutorial/libserver.py
https://github.com/realpython/materials/blob/master/python-sockets-tutorial/libclient.py

You can report issues and problems here, but we typically won't be able to provide 1:1 support outside the channels listed above.

Describe the bug
I am trying to use the appclient and appserver demo from the above sockets tutorial and want to process a custom function using the data read from the server read or client read.

To Reproduce
NA

Expected behavior
Able to run a custom function after a read is done in server or client using the data read.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6] NA
• OS: [e.g. iOS8.1] Linux, Windows
• Browser [e.g. stock browser, safari] NA
• Version [e.g. 22] NA

Additional context
NA

Lee app-server.py y app-client.py junto con libserver.py y libclient.py para entender cómo se leen actualmente los datos del socket. Define y documenta el comportamiento previsto de los controladores de lectura personalizados tanto para el servidor como para el cliente, demostrando la finalización mediante el procesamiento de los datos después de una lectura.