: std::get<gcs::ObjectMetadata>(value).name();
    auto pos = children.find(prefix);
    if (pos != 0) {
      TF_SetStatus(status, TF_INTERNAL,
                   absl::StrCat("Unexpected response: the returned file name ",
                                children, " doesn't match the prefix ", prefix)
                       .c_str());
      return result;
    }
    children.erase(0, prefix.length());