title: Fuel get the body response on error
body: <p>How can I achieve this? This is the request im doing.</p>
  
  <pre><code>Fuel.get(url)
      .timeout(TIMEOUT)
      .body(myRequest.parameters!!, Charsets.UTF_8)
      .responseString() { _, response, result -&gt;
                  Log.e("result", "$result")
                  when (result) {
                      is Result.Success -&gt; {
                          completionHandler(result.get(), null)
                      }
                      is Result.Failure -&gt; {
                          Log.e("fail", "${response}")
                          completionHandler(null, Error(response.responseMessage))
                      }
                  }
              }
  </code></pre>
  
  <p>And the response im getting is:</p>
  
  <pre><code>Response : Bad Request
  Length : 122
  Body : ({"message":"You have already booked that iceCream"})
  Headers : (9)
  Connection : [keep-alive]
  Content-Length : [122]
  Content-Type : [application/json; charset=utf-8]
  Date : [Thu, 03 May 2018 07:33:21 GMT]
  Server : [nginx/1.12.1]
  </code></pre>
  
  <p>I want to return the body message as my error.</p>