c++ - Are there any good ideas for multi-threaded socket sending and receiving?

Question

A is the client’s socket
B is the server’s socket
A connect B TCP connection

Equal to A B establishing a tunnel

Various local requests are made to A, relayed to B for post-processing, and a bunch of data is returned

Then the question comes,
Is there any good solution to distinguish this pile of data and reply to the initiator?

Answer 1

zeromq

Answer 2

Use higher-level protocols, such as HTTP.
Otherwise, encapsulate additional information (ID, type, ...) in request and response?