@NonNullApi
public class AggregatingProblemConsumer {
    private final Multimap<String, InternalProblemEventVersion2> seenProblems = ArrayListMultimap.create();
    private final ProgressEventConsumer progressEventConsumer;
    private final Supplier<OperationIdentifier> operationIdentifierSupplier;
    private int thresholdForIntermediateSummary = 10_000;

class AggregatingProblemConsumerTest extends Specification {
    def "distinct events are not aggregated"() {
        given:
        def eventConsumer = Mock(ProgressEventConsumer)
        def emitter = new AggregatingProblemConsumer(eventConsumer, { new OperationIdentifier(1) })


        when:
        for (int i = 0; i < 3; i++) {
            emitter.emit(createMockProblem("foo$i"))
        }

        then:

        Supplier<OperationIdentifier> operationIdentifierSupplier = () -> new OperationIdentifier(idFactory.nextId());
        AggregatingProblemConsumer aggregator = new AggregatingProblemConsumer(progressEventConsumer, operationIdentifierSupplier);
        this.problemAggregator = Optional.of(aggregator);

    private final Supplier<OperationIdentifier> operationIdentifierSupplier;
    private final AggregatingProblemConsumer aggregator;

    ProblemsProgressEventConsumer(ProgressEventConsumer progressEventConsumer, Supplier<OperationIdentifier> operationIdentifierSupplier, AggregatingProblemConsumer aggregator) {
        super(progressEventConsumer);
        this.operationIdentifierSupplier = operationIdentifierSupplier;