public function toINI()
    {
        $smBody = str_replace("\n", chr(6), $this->smbody);

        $ini = '';
        $ini .= "dstaddr={$this->dstaddr}\n";
        $ini .= "smbody={$smBody}\n";
        if (!empty($this->dlvtime)) {
            $ini .= "dlvtime={$this->dlvtime}\n";
        }
        if (!empty($this->vldtime)) {
            $ini .= "vldtime={$this->vldtime}\n";
        }
        if (!empty($this->response)) {
            $ini .= "response={$this->response}\n";
        }

        return $ini;
    }