Looks like socket heartbeating has been added in this release of ZMQ. From what I can gather from the docs this should address the issue the parent post presents, but does anyone know definitively? See new ZMQ_HEARTBEAT_* options here [0] and Connection Heartbeating section here [1].
[0] http://api.zeromq.org/4-2:zmq-setsockopt [1] https://rfc.zeromq.org/spec:37/ZMTP/