/**
   * Returns a tree traverser that uses the given function to navigate from a node to its children.
   * This is useful if the function instance already exists, or so that you can supply a lambda
   * expressions. If those circumstances don't apply, you probably don't need to use this; subclass
   * {@code TreeTraverser} and implement its {@link #children} method directly.
   *
   * @since 20.0

   * call cancel() and be unable to cancel the delegate.
   * There are a number of ways to solve this, none of which are very pretty, and it is currently
   * believed to be a purely theoretical problem (since the other actions should supply sufficient
   * write-barriers).
   */

  @CheckForNull @LazyInit private ListenableFuture<V> delegateRef;
  @CheckForNull @LazyInit private ScheduledFuture<?> timer;

      FeatureSpecificTestSuiteBuilder<
              ?, ? extends OneSizeTestContainerGenerator<Map<K, V>, Entry<K, V>>>
          parentBuilder) {
    // TODO: Once invariant support is added, supply invariants to each of the
    // derived suites, to check that mutations to the derived collections are
    // reflected in the underlying map.

    List<TestSuite> derivedSuites = super.createDerivedSuites(parentBuilder);

   * call cancel() and be unable to cancel the delegate.
   * There are a number of ways to solve this, none of which are very pretty, and it is currently
   * believed to be a purely theoretical problem (since the other actions should supply sufficient
   * write-barriers).
   */

  @CheckForNull @LazyInit private ListenableFuture<V> delegateRef;
  @CheckForNull @LazyInit private ScheduledFuture<?> timer;

  protected List<TestSuite> createDerivedSuites(
      FeatureSpecificTestSuiteBuilder<?, ? extends OneSizeTestContainerGenerator<M, Entry<K, V>>>
          parentBuilder) {
    // TODO: Once invariant support is added, supply invariants to each of the
    // derived suites, to check that mutations to the derived collections are
    // reflected in the underlying map.

    List<TestSuite> derivedSuites = super.createDerivedSuites(parentBuilder);

	c.Cancel = func() error { return c.Process.Signal(os.Interrupt) }
	c.Dir = dir
	c.Stdin = stdin
	c.Stderr = &stderr
	c.Stdout = &stdout
	// For Git commands, manually supply GIT_DIR so Git works with safe.bareRepository=explicit set. Noop for other commands.
	c.Env = append(c.Environ(), "GIT_DIR="+dir)
	err := c.Run()
	if err != nil {

  protected List<TestSuite> createDerivedSuites(
      FeatureSpecificTestSuiteBuilder<?, ? extends OneSizeTestContainerGenerator<M, Entry<K, V>>>
          parentBuilder) {
    // TODO: Once invariant support is added, supply invariants to each of the
    // derived suites, to check that mutations to the derived collections are
    // reflected in the underlying map.

    List<TestSuite> derivedSuites = super.createDerivedSuites(parentBuilder);

  // Static converters

  /**
   * Returns a converter based on separate forward and backward functions. This is useful if the
   * function instances already exist, or so that you can supply lambda expressions. If those
   * circumstances don't apply, you probably don't need to use this; subclass {@code Converter} and
   * implement its {@link #doForward} and {@link #doBackward} methods directly.
   *

	return tags, nil
}

// repoSum returns a checksum of the entire repo state,
// which can be checked (as Origin.RepoSum) to cache
// the absence of a specific module version.
// The caller must supply refs, the result of a successful r.loadRefs.
func (r *gitRepo) repoSum(refs map[string]string) string {
	var list []string
	for ref := range refs {
		list = append(list, ref)
	}
	sort.Strings(list)

  // Static converters

  /**
   * Returns a converter based on separate forward and backward functions. This is useful if the
   * function instances already exist, or so that you can supply lambda expressions. If those
   * circumstances don't apply, you probably don't need to use this; subclass {@code Converter} and
   * implement its {@link #doForward} and {@link #doBackward} methods directly.
   *