title: Handling specific errors by sending another request transparently in retrofit
body: <p>Here's the case I'm trying to handle,</p>
  
  <ul>
  <li>If a request is executed, and the response indicates the auth token is expired,</li>
  <li>send a refresh token request</li>
  <li>if the refresh token request succeeds, retry the original request</li>
  </ul>
  
  <p>This should be transparent to the calling Activity, Fragment... etc. From the caller's point of view, it's one request, and one response.</p>
  
  <p>I've achieved this flow before when using OkHttpClient directly, but I don't know how to achieve this in Retrofit.</p>
  
  <p>Maybe something related to this open <a href="https://github.com/square/retrofit/issues/261" rel="noreferrer">issue</a> about a ResponseInterceptor?</p>
  
  <p>If there's no straight-forward way to achieve this in retrofit, what would be the best way to implement it? A base listener class?</p>
  
  <p>I'm using RoboSpice with Retrofit as well, if it can be helpful in such case.</p>