SlightPHP\PHPMailer::GetMailMIME PHP Method

    public function GetMailMIME()
    {
        $result = '';
        switch ($this->message_type) {
            case 'plain':
                $result .= $this->HeaderLine('Content-Transfer-Encoding', $this->Encoding);
                $result .= sprintf("Content-Type: %s; charset=\"%s\"", $this->ContentType, $this->CharSet);
                break;
            case 'attachments':
                /* fall through */
            /* fall through */
            case 'alt_attachments':
                if ($this->InlineImageExists()) {
                    $result .= sprintf("Content-Type: %s;%s\ttype=\"text/html\";%s\tboundary=\"%s\"%s", 'multipart/related', $this->LE, $this->LE, $this->boundary[1], $this->LE);
                } else {
                    $result .= $this->HeaderLine('Content-Type', 'multipart/mixed;');
                    $result .= $this->TextLine("\tboundary=\"" . $this->boundary[1] . '"');
                }
                break;
            case 'alt':
                $result .= $this->HeaderLine('Content-Type', 'multipart/alternative;');
                $result .= $this->TextLine("\tboundary=\"" . $this->boundary[1] . '"');
                break;
        }
        if ($this->Mailer != 'mail') {
            $result .= $this->LE . $this->LE;
        }
        return $result;
    }