if (downloadMonitor != null) {
            wagon.addTransferListener(downloadMonitor);
        }

        Map<String, ChecksumObserver> checksums = new HashMap<>(2);

        Map<String, String> sums = new HashMap<>(2);

        // TODO configure these on the repository
        for (int i = 0; i < CHECKSUM_IDS.length; i++) {
            checksums.put(CHECKSUM_IDS[i], addChecksumObserver(wagon, CHECKSUM_ALGORITHMS[i]));