code: private static RqFallback.Fake fallback(final Request req, final long start,
          final Throwable throwable, final int code) throws IOException {
          return new RqFallback.Fake(
              req, code, TkFallback.error(throwable, req, start)
          );
      }
docs: Fallback request.
  @param req Request
  @param start Start time of request processing
  @param throwable Exception thrown
  @param code Error code
  @return Fallback request
  @throws IOException In case of error
  @checkstyle ParameterNumber (3 lines)