event.setDataLength(length);
        event.setTransferredBytes(transferred);

        listener.transferProgress(event);
    }

    @Override
    public void transferStarted(TransferEvent transferEvent) {
        listener.transferStarted(wrap(transferEvent));
    }

    private ArtifactTransferEvent wrap(TransferEvent event) {
        if (event == null) {
            return null;
        } else {