code: private boolean hasToCaptureOutput() {
          return !proxy || contentTypeHelper.isTextContentType(httpClientResponse)
                  || HttpResponseUtils.getFirstHeader(HttpHeaders.CONTENT_TYPE, httpClientResponse) == null;
      }
docs: We have to capture the output of the response in 2 cases :
  <ol>
  <li>the content type is text and may have to be transformed</li>
  <li>we are inside an include, in this case the content type must be considered as text</li>
  </ol>
  
  @return true if we have to capture the output of the response