for {
		select {
		case event := <-wk.dirWatcher.Events:
			// work on a copy of the watchedFiles map, so that we don't interfere
			// with the caller's use of the map
			for path, ft := range wk.getTrackers() {
				if ft.events == nil {
					// tracker has been retired, skip it
					continue
				}

				sum := getHashSum(path)
				if !bytes.Equal(sum, ft.hash) {
					ft.hash = sum

					select {

     * build operation execution. If this tracker is not required, the trackers can be ignored.
     */
    default List<? extends BuildOperationTracker> getTrackers() {
        return Collections.emptyList();
    }

    void started(BuildOperationDescriptor buildOperation, OperationStartEvent startEvent);

            if (mapper.isEnabled(subscriptions)) {
                mapperBuilder.add(new Enabled(mapper, progressEventConsumer));
                collectTrackers(trackers, mapper.getTrackers());
            } else {
                mapperBuilder.add(new Disabled(mapper));
            }
        }
        this.mappers = ImmutableList.copyOf(mapperBuilder);

    TaskOriginTracker(PluginApplicationTracker pluginApplicationTracker) {
        this.pluginApplicationTracker = pluginApplicationTracker;
    }

    @Override
    public List<? extends BuildOperationTracker> getTrackers() {
        return ImmutableList.of(pluginApplicationTracker);
    }

    @Nullable
    InternalPluginIdentifier getOriginPlugin(TaskIdentity<?> taskIdentity) {
        return origins.get(taskIdentity.uniqueId);

     * build operation execution. If this mapper is not enabled, the trackers can be ignored.
     */
    default List<? extends BuildOperationTracker> getTrackers() {
        return Collections.emptyList();
    }

    /**
     * Maps the descriptor for the given build operation.
     */

    @Override
    public Class<ConfigureProjectBuildOperationType.Details> getDetailsType() {
        return ConfigureProjectBuildOperationType.Details.class;
    }

    @Override
    public List<BuildOperationTracker> getTrackers() {
        return ImmutableList.of(projectConfigurationTracker);
    }

    @Override

        this.ancestryTracker = ancestryTracker;
        this.pluginApplicationTracker = pluginApplicationTracker;
    }

    @Override
    public List<? extends BuildOperationTracker> getTrackers() {
        return ImmutableList.of(pluginApplicationTracker);
    }

    public List<InternalPluginApplicationResult> resultsFor(OperationIdentifier buildOperation) {

    @Override
    public Class<ExecuteTaskBuildOperationDetails> getDetailsType() {
        return ExecuteTaskBuildOperationDetails.class;
    }

    @Override
    public List<? extends BuildOperationTracker> getTrackers() {
        return ImmutableList.of(taskOriginTracker, operationResultPostProcessor);
    }

    @Override
    public InternalOperationDescriptor lookupExistingOperationDescriptor(Node node) {

    @Override
    public Class<ExecuteTestBuildOperationType.Details> getDetailsType() {
        return ExecuteTestBuildOperationType.Details.class;
    }

    @Override
    public List<? extends BuildOperationTracker> getTrackers() {
        return ImmutableList.of(taskTracker);
    }

    @Override