wp_queue_comments_for_comment_meta_lazyload

 * @return int|bool Meta ID if the key didn't exist, true on successful update,
 *                  false on failure or if the value passed to the function
 *                  is the same as the one that is already in the database.
 */
function update_comment_meta( $comment_id, $meta_key, $meta_value, $prev_value = '' ) {
	return update_metadata( 'comment', $comment_id, $meta_key, $meta_value, $prev_value );
}

/**
 * Queues comments for metadata lazy-loading.
 *
 * @since 4.5.0
 *
 * @param WP_Comment[] $comments Array of comment objects.
 */
function wp_queue_comments_for_comment_meta_lazyload( $comments ) {