name: Switch to system preference
  features:
  - content.code.annotate
  - content.code.copy
  - content.footnote.tooltips
  - content.tabs.link
  - content.tooltips
  - navigation.footer
  - navigation.indexes
  - navigation.instant
  - navigation.instant.prefetch
  - navigation.instant.progress
  - navigation.path
  - navigation.tabs
  - navigation.tabs.sticky
  - navigation.top
  - navigation.tracking

    }

    /**
     * Indexes a document asynchronously.
     *
     * @param request the index request
     * @return a future for the index response
     */
    @Override
    public ActionFuture<IndexResponse> index(final IndexRequest request) {
        return client.index(request);
    }

    /**
     * Indexes a document asynchronously with a callback.
     *