class DevelopmentMailInterceptor
  def self.delivering_email(message)
 
    filteredMailers = %w[
      NotificationMailer
    ]
 
    if filteredMailers.include?(message.delivery_handler)
      message.subject = "[filter] To:#{message.to} - #{message.subject}"
      message.to = 'logs@mail.com'
    end
 
    return message
  end
end

@ Intrepidd的答案仍然是正确的,因为拦截器应用于整个Mail类,但我找到了我希望实现的方法.