}
    }

    @Override
    public void transferFailed(TransferEvent event) {
        transferCompleted(event);

        println(
                "transferFailed",
                event.getException().getClass() + ": " + event.getException().getMessage());
    }

    private void transferCompleted(TransferEvent event) {
        downloads.remove(event.getResource());

        this.artifacts = new IdentityHashMap<>();
        this.transfers = new IdentityHashMap<>();
    }

    @Override
    public void debug(String message) {}

    @Override
    public void transferCompleted(TransferEvent transferEvent) {
        ArtifactTransferEvent event = wrap(transferEvent);

        Long transferred;
        synchronized (transfers) {