Concurrent Document Mutations

{
    lcb_CMDGET *cmd = nullptr;
    check(lcb_cmdget_create(&cmd), "create GET command");
    check(lcb_cmdget_key(cmd, document_id.data(), document_id.size()),
          "assign ID for GET command");
    /**
     * Time in seconds, note that the server might reset time to default, if it larger than
     * maximum time (both durations are configurable). The following command will help to
     * discover effective values for the feature.
     *
     * $ cbstats -u Administrator -p password  localhost all | grep ep_getl
     * ep_getl_default_timeout:                               15
     * ep_getl_max_timeout:                                   30
     */
    check(lcb_cmdget_locktime(cmd, 5), "lock for 5 seconds");
    check(lcb_get(local_instance, &result, cmd), "schedule GET command");
    check(lcb_cmdget_destroy(cmd), "destroy GET command");
    lcb_wait(local_instance, LCB_WAIT_DEFAULT);

    if (result.rc == LCB_ERR_DOCUMENT_LOCKED
        || result.rc == LCB_ERR_TEMPORARY_FAILURE) {
        std::stringstream msg;
        msg << "Document is locked for " << item_value
            << ". Retrying in 100 milliseconds...\n";
        std::cout << msg.str();
        std::this_thread::sleep_for(std::chrono::milliseconds(100));
        continue;
    } else {
        check(result.rc, "could not find list document");
    }
    cas = result.cas;
}

    check(lcb_cmdstore_cas(cmd, cas), "assign CAS value for REPLACE command");