Dsn example

$emailAgent = $this->configService->getString('core.mailerSettings.emailAgent');

        return match ($emailAgent) {
            'smtp' => $this->createSmtpTransport($this->configService),
            'local' => new SendmailTransport($this->getSendMailCommandLineArgument($this->configService)),
            default => throw new \RuntimeException(sprintf('Invalid mail agent given "%s"', $emailAgent)),
        };
    }

    private function createSmtpTransport(SystemConfigService $configService): TransportInterface
    {
        $dsn = new Dsn(
            $this->getEncryption($configService) === 'ssl' ? 'smtps' : 'smtp',
            $configService->getString('core.mailerSettings.host'),
            $configService->getString('core.mailerSettings.username'),
            $configService->getString('core.mailerSettings.password'),
            $configService->getInt('core.mailerSettings.port'),
            $this->getEncryption($configService) !== null ? [] : ['verify_peer' => 0]
        );

        return $this->envBasedTransport->fromDsnObject($dsn);
    }