code: private static String message(final String reason, final int status, @Nullable  final String tail) {
      return reason + "(" + status + ")" + (tail == null ? "" : ": " + tail);
    }
docs: Build an error message using the HTTP status.
  
  @param reason Reason.
  @param status The Status.
  @param tail A message to append.
  @return An error message.