}

    /**
     * Whether this progress start represent the start of a build operation,
     * as opposed to a progress operation within a build operation.
     */
    public boolean isBuildOperationStart() {
        return buildOperationStart;
    }

    /**
     * When this event is a build operation start event, this property will be non-null and will have the same value as {@link #getProgressOperationId()}.

    @Override
    public void onOutput(OutputEvent event) {
        if (event instanceof ProgressStartEvent) {
            ProgressStartEvent startEvent = (ProgressStartEvent) event;
            if (!startEvent.isBuildOperationStart()) {
                forwarded.add(startEvent.getProgressOperationId());
                OperationIdentifier parentProgressOperationId = startEvent.getParentProgressOperationId();

    @Override
    public void onOutput(OutputEvent event) {
        if (event instanceof ProgressStartEvent) {
            ProgressStartEvent startEvent = (ProgressStartEvent) event;
            if (startEvent.isBuildOperationStart()) {
                if (buildStartTimestamp == 0 && startEvent.getParentProgressOperationId() == null) {
                    // The very first event starts the Initializing phase

        BuildOperationCategory buildOperationCategory = event.getBuildOperationCategory();
        flags |= (buildOperationCategory.ordinal() & BUILD_OP_CATEGORY_MASK) << BUILD_OP_CATEGORY_OFFSET;

        if (event.isBuildOperationStart()) {
            flags |= BUILD_OPERATION_START;
        }

        if (event.getCategory().equals(ProgressStartEvent.BUILD_OP_CATEGORY)) {
            flags |= CATEGORY_IS_BUILD_OP;

        boolean isGrouped = startEvent.getBuildOperationCategory().isGrouped();
        OperationIdentifier progressId = startEvent.getProgressOperationId();
        if (startEvent.isBuildOperationStart() && isGrouped) {
            // Create a new group for tasks or configure project