private void init (int ops) {
        zinterest = ops;
        int interest_ = 0;
        if ((ops & ZMQ.ZMQ_POLLIN) > 0) {
            interest_ |= SelectionKey.OP_READ ;
        }
        if ((ops & ZMQ.ZMQ_POLLOUT) > 0) {
            if (s != null)  //  ZMQ Socket get readiness from the mailbox
                interest_ |= SelectionKey.OP_READ ;
            else
                interest_ |= SelectionKey.OP_WRITE;
        }
        interest = interest_;
        ready = 0;
    }