Issue #3420372 by drubb, jurgenhaas, znerol, m.stenta, mkdok: Core Symfony...

      // mails into the code path (i.e., event subscribers) of the new API.

      // Therefore, this plugin deliberately refrains from injecting the event

      // dispatcher.

      $factories = Transport::getDefaultFactories(logger: $this->logger);

      $factories = Transport::getDefaultFactories();

      $transportFactory = new Transport($factories);

      $transport = $transportFactory->fromDsnObject($dsnObject);

      $this->mailer = new Mailer($transport);