// nothing
    }

    /**
     * A list of Throwables representing failures that occurred during the operation.
     */
    protected List<Throwable> failures = Collections.synchronizedList(new ArrayList<>());

    /**
     * Adds a Throwable to the list of failures.
     *
     * @param t the Throwable to add
     */
    public void addFailure(final Throwable t) {
        failures.add(t);