Taken from https://github.com/ph4r05/py-chacha20poly1305.
Note that this is different from the ChaCha20 implementation
used in Bitcoin Core since this:
1. uses a 96 bit nonce (instead of a 64 bit nonce)
2. does not reuse existing keystream

That is, allow 64 bit nonce and keystream reuse.

The server creates a new unix domain socket which will listen
and accept client connections. Based on the chacha20 operation
the client(fuzz target) requests, it performs chacha20 operations
parallelly using the python chacha20 implementation and sends back
the response(like keystream, ciphertext) back to the client(fuzz target).

This behaves like the client and sends requests to the python server
file (src/test/fuzz/script.py) to perform certain operations,
receives python output computed in the server file and compares both
to see if they match.