Don't send email and return HTML

I need to get HTML before to send email

Using this code I can build and send an email via the Email Factory :

    // Prepare the edition.
    $emailFactory = \Drupal::service('email_factory');
    $email = $emailFactory->newTypedEmail('type', 'subtype');
    $email->setSubject('Test subject');
    $email->setTo('mymail');
    $email->send();

I need to get the full html code of the email before that it sended. I tried tu use several method without success.

With this module can I get the html of the email?

Thanks for your help .