Jyxo\Mail\Sender::getBoundaryStart PHP Метод

    private function getBoundaryStart(string $boundary, string $contentType, string $charset, string $encoding) : string
    {
        $start = '--' . $boundary . self::LINE_END;
        $start .= 'Content-Type: ' . $contentType . '; charset="' . $this->clearHeaderValue($charset) . '"' . self::LINE_END;
        $start .= 'Content-Transfer-Encoding: ' . $encoding . self::LINE_END;
        return $start;
    }