public static function logProfiling(array $log_data)
    {
        if (self::$profiling_count > self::$profiling_max) {
            return;
        }

        self::$profiling_count++;
        if (isset($log_data['errorno'])) {
            self::$profiling[] = array(
                'url'       => $log_data['url'],
                'errorno'   => $log_data['errorno'],
                'error'     => $log_data['error'],
                'queue'     => $log_data['queue'],
            );
        } else {
            self::$profiling[] = array(
                'url'               => $log_data['url'],
                'http_code'         => $log_data['http_code'],
                'total_time'        => $log_data['total_time'],
                'pretransfer_time'  => $log_data['pretransfer_time'],
                'queue'             => $log_data['queue'],
            );
        }
    }