C library and/or protocol description for foreign clients

Feature Proposed

I'd like to see a C library and/or a protocol description to integrate foreign clients.

Use Case

I'd like to directly connect to rathole from platforms where I can't install anything, e.g. iOS and/or microcontrollers, such as the ESP32 family of devices. For that I wonder whether a C library and/or a protocol description would be feasible, so that we could write our own clients that talk to rathole.