SMimePart example

            if (preg_match('/(\r\n\r\n|\n\n)/', $headers, $match)) {
                $headersPosEnd = strpos($headers, $headerBodySeparator = $match[0]);

                break;
            }
        }

        $headers = $this->getMessageHeaders(trim(substr($headers, 0, $headersPosEnd)));

        fseek($stream, $headersPosEnd + \strlen($headerBodySeparator));

        return new SMimePart($this->getStreamIterator($stream), $type, $subtype, $this->getParametersFromHeader($headers['content-type']));
    }

    protected function getStreamIterator($stream): iterable
    {
        while (!feof($stream)) {
            yield str_replace("\n", "\r\n", str_replace("\r\n", "\n", fread($stream, 16372)));
        }
    }

    private function getMessageHeaders(string $headerData): array
    {
        

            if (preg_match('/(\r\n\r\n|\n\n)/', $headers, $match)) {
                $headersPosEnd = strpos($headers, $headerBodySeparator = $match[0]);

                break;
            }
        }

        $headers = $this->getMessageHeaders(trim(substr($headers, 0, $headersPosEnd)));

        fseek($stream, $headersPosEnd + \strlen($headerBodySeparator));

        return new SMimePart($this->getStreamIterator($stream), $type, $subtype, $this->getParametersFromHeader($headers['content-type']));
    }

    protected function getStreamIterator($stream): iterable
    {
        while (!feof($stream)) {
            yield str_replace("\n", "\r\n", str_replace("\r\n", "\n", fread($stream, 16372)));
        }
    }

    private function getMessageHeaders(string $headerData): array
    {