code: private void setHeaders(final HttpServletResponse response,
              final Root root) {
          response.setHeader("content-type", "application/octet-stream");
          response.setHeader("content-disposition",
                  "attachment; filename=" + getSaveFilename(root));
      }
docs: Fill in response headers to make this save the file instead of
  displaying it.
  
  @param response the servlet response
  @param root the root of the dataset being saved