zeromq.device documentation

proxy

(proxy context frontend backend)(proxy context frontend backend capture)
The proxy function starts the built-in ØMQ proxy in the current application
 thread.

The proxy connects a frontend socket to a backend socket. Conceptually, data
flows from frontend to backend. Depending on the socket types, replies may
flow in the opposite direction. The direction is conceptual only; the proxy
is fully symmetric and there is no technical difference between frontend and
backend.

Before calling proxy you must set any socket options, and connect or bind
both frontend and backend sockets. The two conventional proxy models are:

proxy runs in the current thread and returns only if/when the current context
is closed.