protected function debug($info, $var = null) 
    {
        if(!$this->debug) {
            return;
        }
        
        print '<b>'.$info.'</b> '.(microtime(1) - $this->start).'s<br />' . "\r\n";
        
        if(!is_null($var)) {
            $content = var_export($var, 1);
            print "<pre>\r\n$content\r\n</pre>\r\n";
        }
    }