void flushSlavesOutputBuffers(void) {
    listIter li;
    listNode *ln;

    listRewind(server.slaves,&li);
    while((ln = listNext(&li))) {
        client *slave = listNodeValue(ln);
        int events;

        /* Note that the following will not flush output buffers of slaves
         * in STATE_ONLINE but having put_online_on_ack set to true: in this
         * case the writable event is never installed, since the purpose
         * of put_online_on_ack is to postpone the moment it is installed.
         * This is what we want since slaves in this state should not receive
         * writes before the first ACK. */
        events = aeGetFileEvents(server.el,slave->fd);
        if (events & AE_WRITABLE &&
            slave->replstate == SLAVE_STATE_ONLINE &&
            clientHasPendingReplies(slave))
        {
            writeToClient(slave->fd,slave,0);
        }
    }
}
void flushSlavesOutputBuffers(void) {
    listIter li;
    listNode *ln;

    listRewind(server.slaves,&li);
    while((ln = listNext(&li))) {
        client *slave = listNodeValue(ln);
        int events;

         
        events = aeGetFileEvents(server.el,slave->fd);
        if (events & AE_WRITABLE &&
            slave->replstate == SLAVE_STATE_ONLINE &&
            clientHasPendingReplies(slave))
        {
            writeToClient(slave->fd,slave,0);
        }
    }
}