public static function memoryUsage(string $point_name) : string
    {
        if (isset(Debug::$memory[$point_name])) {
            $unit = array('B', 'KB', 'MB', 'GB', 'TiB', 'PiB');
            $size = memory_get_usage() - Debug::$memory[$point_name];
            $memory_usage = @round($size/pow(1024, ($i=floor(log($size, 1024)))), 2).' '.$unit[($i < 0 ? 0 : $i)];
            return $memory_usage;
        }
    }