int writeToClient(int fd, client *c, int handler_installed) {
    ssize_t nwritten = 0, totwritten = 0;
    size_t objlen;
    size_t objmem;
    robj *o;

    while(clientHasPendingReplies(c)) {
        if (c->bufpos > 0) {
            nwritten = write(fd,c->buf+c->sentlen,c->bufpos-c->sentlen);
            if (nwritten <= 0) break;
            c->sentlen += nwritten;
            totwritten += nwritten;

            /* If the buffer was sent, set bufpos to zero to continue with
             * the remainder of the reply. */
            if ((int)c->sentlen == c->bufpos) {
                c->bufpos = 0;
                c->sentlen = 0;
            }
        } else {
            o = listNodeValue(listFirst(c->reply));
            objlen = sdslen(o->ptr);
            objmem = getStringObjectSdsUsedMemory(o);

            if (objlen == 0) {
                listDelNode(c->reply,listFirst(c->reply));
                c->reply_bytes -= objmem;
                continue;
            }

            nwritten = write(fd, ((char*)o->ptr)+c->sentlen,objlen-c->sentlen);
            if (nwritten <= 0) break;
            c->sentlen += nwritten;
            totwritten += nwritten;

            /* If we fully sent the object on head go to the next one */
            if (c->sentlen == objlen) {
                listDelNode(c->reply,listFirst(c->reply));
                c->sentlen = 0;
                c->reply_bytes -= objmem;
            }
        }
        /* Note that we avoid to send more than NET_MAX_WRITES_PER_EVENT
         * bytes, in a single threaded server it's a good idea to serve
         * other clients as well, even if a very large request comes from
         * super fast link that is always able to accept data (in real world
         * scenario think about 'KEYS *' against the loopback interface).
         *
         * However if we are over the maxmemory limit we ignore that and
         * just deliver as much data as it is possible to deliver. */
        server.stat_net_output_bytes += totwritten;
        if (totwritten > NET_MAX_WRITES_PER_EVENT &&
            (server.maxmemory == 0 ||
             zmalloc_used_memory() < server.maxmemory)) break;
    }
    if (nwritten == -1) {
        if (errno == EAGAIN) {
            nwritten = 0;
        } else {
            serverLog(LL_VERBOSE,
                "Error writing to client: %s", strerror(errno));
            freeClient(c);
            return C_ERR;
        }
    }
    if (totwritten > 0) {
        /* For clients representing masters we don't count sending data
         * as an interaction, since we always send REPLCONF ACK commands
         * that take some time to just fill the socket output buffer.
         * We just rely on data / pings received for timeout detection. */
        if (!(c->flags & CLIENT_MASTER)) c->lastinteraction = server.unixtime;
    }
    if (!clientHasPendingReplies(c)) {
        c->sentlen = 0;
        if (handler_installed) aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);

        /* Close connection after entire reply has been sent. */
        if (c->flags & CLIENT_CLOSE_AFTER_REPLY) {
            freeClient(c);
            return C_ERR;
        }
    }
    return C_OK;
}

This label identifies security gaps where expected security features are missing or only partially implemented, reducing protection against unauthorized access or manipulation.