class LoggingTransactionalMailer < TransactionalMailer
  def send_mail(user,mail)
    p "sending email to user #{user.id}"
    super(user.email, mail.body)
  end
end

class BlockingLoggingTransactionalMailer < LoggingTransactionalMailer
  def send_mail(user,mail)
    return uless @user.has_active_subscription?
    super(user.email, mail.body)
  end
end