private function post_to_sitemap_item( $post ) {

    
/**
 * Filter condition to allow skipping specific posts in sitemap.
 *
 * @module sitemaps
 *
 * @since 3.9.0
 *
 * @param bool   $skip Current boolean. False by default, so no post is skipped.
 * @param object $post Current post in the form of a $wpdb result object. Not WP_Post.
 */
    if ( true === apply_filters( 'jetpack_sitemap_skip_post', false, $post ) ) {
      return array(
        'xml'           => null,
        'last_modified' => null,
      );
    }

    $url = esc_url( get_permalink( $post ) );

    /*
		 * Spec requires the URL to be <=2048 bytes.
		 * In practice this constraint is unlikely to be violated.
		 */
    if ( 2048 < strlen( $url ) ) {
      $url = home_url() . '/?p=' . $post->ID;
    }

    $last_modified = $post->post_modified_gmt;

    // Check for more recent comments.
    // Note that 'Y-m-d h:i:s' strings sort lexicographically.
    if ( 0 < $post->comment_count ) {
      $last_modified = max(
        $last_modified,
        $this->librarian->query_latest_approved_comment_time_on_post( $post->ID )
      );
    }

    $item_array = array(
      'url' => array(
        'loc'     => $url,
        'lastmod' => jp_sitemap_datetime( $last_modified ),
      ),
    );

    
/**
 * Filter sitemap URL item before rendering it as XML.
 *
 * @module sitemaps
 *
 * @since 3.9.0
 *
 * @param array $tree Associative array representing sitemap URL element.
 * @param int   $post_id ID of the post being processed.
 */
    $item_array = apply_filters( 'jetpack_sitemap_url', $item_array, $post->ID );

    return array(
      'xml'           => $item_array,
      'last_modified' => $last_modified,
    );
  }