title: Retrofit 2 Callback onResponse on background thread
body: <p>This has probably been asked before but didn't seem to have a viable answer. We are using Retrofit 2.1.0 async callback which carries out the request on the background thread. However, when the response is received <code>onResponse</code> it is sent back on the application's UI thread regardless of me placing the callback within a new thread forcing it to not utilize the UI.</p>
  
  <p>As we don't want to block the main UI thread for any reason, is it possible for the response to be returned in the background?</p>
  
  <p>If the above is not possible, is it recommended that a separate thread is kicked off from the response in order to avoid UI thread blocking?</p>
  
  <p>Any help would be much appreciated. Thanks!</p>