private function convertEncoding()
    {
        $convert = new EncodingHandler($this->content, $this->encoding);
        if (($result = $convert->auto()) !== false) {
            $this->encoding = self::ENCODING;
            mb_internal_encoding(self::ENCODING);
            return $this->content = $result;
        }
        mb_internal_encoding(self::ENCODING);
        return $this->content;
    }