public static final void sendByteArray(long s, int size) {
        byte[] bb = new byte[size];
        int rc = zmq_send(s, bb, 0, size, 0);
        if (rc < 0) {
            System.out.println("error in zmq_sendmsg: " + zmq_strerror(zmq_errno()));
            System.exit(-1);
        }
    }