code: static void configureForwarding(@Nonnull final Email email, @Nonnull final MimeMultipart multipartRootMixed) throws MessagingException {
  		if (email.getEmailToForward() != null) {
  			final BodyPart fordwardedMessage = new MimeBodyPart();
  			fordwardedMessage.setContent(email.getEmailToForward(), "message/rfc822");
  			multipartRootMixed.addBodyPart(fordwardedMessage);
  		}
  	}
docs: If provided, adds the {@code emailToForward} as a MimeBodyPart to the mixed multipart root.
  <p>
  <strong>Note:</strong> this is done without setting {@code Content-Disposition} so email clients can choose
  how to display embedded forwards. Most client will show the forward as inline, some may show it as attachment.