public void reset() {
        this.computedUpperBound = 0;
        this.uncertaintyFactor = UNCERTAINTY_FACTOR_MAX;
    }
The progress bar maintains state of the highest seen upper bound
so that it can show the latest information about the source. This
resets that state.
stroom-core-client-widget/src/main/java/stroom/widget/progress/client/presenter/ProgressPresenter.java