WordPress at a glance
function is not described

wp_throttle_comment_flood() WP 2.1.0

Whether a comment should be blocked because of comment flood.

No Hooks.

Return

true/false. Whether comment should be blocked.

Usage

wp_throttle_comment_flood( $block, $time_lastcomment, $time_newcomment );
$block(true/false) (required)
Whether plugin has already blocked comment.
$time_lastcomment(int) (required)
Timestamp for last comment.
$time_newcomment(int) (required)
Timestamp for new comment.

Code of wp throttle comment flood: wp-includes/comment.php VER 5.1.1

<?php
function wp_throttle_comment_flood( $block, $time_lastcomment, $time_newcomment ) {
	if ( $block ) { // a plugin has already blocked... we'll let that decision stand
		return $block;
	}
	if ( ( $time_newcomment - $time_lastcomment ) < 15 ) {
		return true;
	}
	return false;
}