The zmq_ctx_shutdown() function shall shutdown the 0MQ context context.
Context shutdown will cause any blocking operations currently in progress on sockets open within context
to return immediately with an error code of ETERM. With the exception of zmq_close(), any further
operations on sockets open within context shall fail with an error code of ETERM. No further sockets can
be created using zmq_socket() on a context for which zmq_ctx_shutdown() has been called, it will return
and set errno to ETERM.
This function is optional, client code is still required to call the zmq_ctx_term(3) function to free all
resources allocated by zeromq.