public function news_sitemap_xml() {
    $the_stored_news_sitemap = get_transient( 'jetpack_news_sitemap_xml' );

    if ( false === $the_stored_news_sitemap ) {

      if ( $this->logger ) {
        $this->logger->report( 'Beginning news sitemap generation.' );
      }

      
/**
 * Filter limit of entries to include in news sitemap.
 *
 * @module sitemaps
 *
 * @since 3.9.0
 *
 * @param int $count Number of entries to include in news sitemap.
 */
      $item_limit = apply_filters(
        'jetpack_sitemap_news_sitemap_count',
        JP_NEWS_SITEMAP_MAX_ITEMS
      );

      $buffer = new Jetpack_Sitemap_Buffer_News(
        min( $item_limit, JP_NEWS_SITEMAP_MAX_ITEMS ),
        JP_SITEMAP_MAX_BYTES
      );

      $posts = $this->librarian->query_most_recent_posts( JP_NEWS_SITEMAP_MAX_ITEMS );

      foreach ( $posts as $post ) {
        $current_item = $this->post_to_news_sitemap_item( $post );

        if ( false === $buffer->append( $current_item['xml'] ) ) {
          break;
        }
      }

      if ( $this->logger ) {
        $this->logger->time( 'End news sitemap generation.' );
      }

      $the_stored_news_sitemap = $buffer->contents();

      set_transient(
        'jetpack_news_sitemap_xml',
        $the_stored_news_sitemap,
        JP_NEWS_SITEMAP_INTERVAL
      );
    } // End if.

    return $the_stored_news_sitemap;
  }