I have looked at zmq before, but have always been stopped by the paradigm mismatch between "people communicating by email", which is the analogy that Messenger Library follows, and "sockets on steroids" that zmq is.
As it says on zeromq.org , "ZeroMQ looks like an embeddable networking library but acts like a concurrency framework." ZeroMQ is a different concurrency framework than an "actor model" motivated one like "Messenger Library". ZMQ seems designed to build more specialist components that my "actors"; with the messaging patterns inherent to the sockets. It is not clear how I can interface these specialist sockets.