title: what is attr_internal used for
body: <p>I am new in ruby on rails while go through rails code I found that </p>
  
  <pre><code>   attr_internal :response_body
    attr_internal :action_name
    attr_internal :formats
  </code></pre>
  
  <p>what is it what does it do ? why they used attr_internal for action dispatch for response body  or action name?</p>