docs: private void validateTrackerResponse(TrackerMessage message)
            throws AnnounceException {
      if (message instanceof ErrorMessage) {
        throw new AnnounceException(((ErrorMessage) message).getReason());
      }
  
      if (message instanceof UDPTrackerMessage &&
              (((UDPTrackerMessage) message).getTransactionId() != this.transactionId)) {
        throw new AnnounceException("Invalid transaction ID!");
      }
    }