ListenerBroadcast<ProjectEvaluationListener> nextBatch = newProjectEvaluationListenerBroadcast();
        this.evaluationListener = nextBatch;
        try {
            step.execute(listener);
        } finally {
            this.evaluationListener = original;
        }
        return nextBatch.isEmpty()
            ? null
            : nextBatch.getSource();
    }