zeromq module thread safety

Hello, We're using mod_event_zmq module (slightly modified, we use different socket type and IPC instead of TCP), and experience crashes. As far as I understood the module it creates ZMQ context and all event sent by using same context. Events callback is called from different threads, isn't it? And can be a situation when different threads access send() api on this context simultaneously. ZMQ guide strongly prohibits doing that: " You MUST NOT share ØMQ sockets between threads." And when I do a mutex around send() there're no more crashes (at least today). Am I missing something or mod_event_zmq is potentially dangerous? -- Best Regards, Alex Massover