private function renderTextAndHtmlWithEmbededFiles(&$content, $text, $html, $encoding, $boundary)
    {
        $uid = uniqid();
        $boundary2 = "x----_=_NextPart_002_$uid";
        $content .= "\r\n--$boundary\r\n";
        $content .= "Content-Type: multipart/related;\r\n\tboundary=\"$boundary2\";\r\n\ttype=\"multipart/alternative\"\r\n";
        $this->renderTextAndHtml($content, $text, $html, $encoding, $boundary2);
        $this->renderEmbeddedFiles($content, $boundary2);
        $content .= "\r\n--$boundary2--\r\n";
    }