code: public static InputStream inputStreamForResponse(InputStream is, AmazonWebServiceRequest req) {
          return req == null
               ? is
               : new ResponseProgressInputStream(is, req.getGeneralProgressListener());
      }
docs: Returns an input stream for response progress tracking purposes. If
  request/response progress tracking is not enabled, this method simply
  return the given input stream as is.
  
  @param is the response content input stream