super.transferSucceeded(event);
    }

    @Override
    public void transferFailed(TransferEvent event) {
        transfers.remove(new TransferResourceIdentifier(event.getResource()));
        overridePreviousTransfer(event);

        super.transferFailed(event);
    }

    private void overridePreviousTransfer(TransferEvent event) {
        if (lastLength > 0) {

                        case SUCCEEDED:
                            delegate.transferSucceeded(transferEvent);
                            break;
                        case FAILED:
                            delegate.transferFailed(transferEvent);
                            break;
                        default:
                            LOGGER.warn("Invalid TransferEvent.EventType={}; ignoring it", type);
                    }

                throw new TransferCancelledException();
            }

            @Override
            public void transferSucceeded(TransferEvent event) {}

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

        try (SimplexTransferListener listener = new SimplexTransferListener(delegate)) {
            TransferResource resource =