SlightPHP\PHPMailer::CreateHeader PHP Method

    public function CreateHeader()
    {
        $result = '';
        /* Set the boundaries */
        $uniq_id = md5(uniqid(time()));
        $this->boundary[1] = 'b1_' . $uniq_id;
        $this->boundary[2] = 'b2_' . $uniq_id;
        $result .= $this->HeaderLine('Date', $this->RFCDate());
        if ($this->Sender == '') {
            $result .= $this->HeaderLine('Return-Path', trim($this->From));
        } else {
            $result .= $this->HeaderLine('Return-Path', trim($this->Sender));
        }
        /* To be created automatically by mail() */
        if ($this->Mailer != 'mail') {
            if (count($this->to) > 0) {
                $result .= $this->AddrAppend('To', $this->to);
            } elseif (count($this->cc) == 0) {
                $result .= $this->HeaderLine('To', 'undisclosed-recipients:;');
            }
            if (count($this->cc) > 0) {
                $result .= $this->AddrAppend('Cc', $this->cc);
            }
        }
        $from = array();
        $from[0][0] = trim($this->From);
        $from[0][1] = $this->FromName;
        $result .= $this->AddrAppend('From', $from);
        /* sendmail and mail() extract Cc from the header before sending */
        if (($this->Mailer == 'sendmail' || $this->Mailer == 'mail') && count($this->cc) > 0) {
            $result .= $this->AddrAppend('Cc', $this->cc);
        }
        /* sendmail and mail() extract Bcc from the header before sending */
        if (($this->Mailer == 'sendmail' || $this->Mailer == 'mail') && count($this->bcc) > 0) {
            $result .= $this->AddrAppend('Bcc', $this->bcc);
        }
        if (count($this->ReplyTo) > 0) {
            $result .= $this->AddrAppend('Reply-to', $this->ReplyTo);
        }
        /* mail() sets the subject itself */
        if ($this->Mailer != 'mail') {
            $result .= $this->HeaderLine('Subject', $this->EncodeHeader($this->SecureHeader($this->Subject)));
        }
        if ($this->MessageID != '') {
            $result .= $this->HeaderLine('Message-ID', $this->MessageID);
        } else {
            $result .= sprintf("Message-ID: <%s@%s>%s", $uniq_id, $this->ServerHostname(), $this->LE);
        }
        $result .= $this->HeaderLine('X-Priority', $this->Priority);
        $result .= $this->HeaderLine('X-Mailer', 'PHPMailer (phpmailer.codeworxtech.com) [version ' . $this->Version . ']');
        if ($this->ConfirmReadingTo != '') {
            $result .= $this->HeaderLine('Disposition-Notification-To', '<' . trim($this->ConfirmReadingTo) . '>');
        }
        // Add custom headers
        for ($index = 0; $index < count($this->CustomHeader); $index++) {
            $result .= $this->HeaderLine(trim($this->CustomHeader[$index][0]), $this->EncodeHeader(trim($this->CustomHeader[$index][1])));
        }
        if (!$this->sign_key_file) {
            $result .= $this->HeaderLine('MIME-Version', '1.0');
            $result .= $this->GetMailMIME();
        }
        return $result;
    }