*
 * This implementation combines the hashes of the children of a directory into a single hash for the directory.
 * For the hash to be reproducible, the children must be sorted in a consistent order.
 * The implementation uses {@link FileSystemLocationSnapshot#BY_NAME} ordering.
 * If you already provide the children in sorted order, use {@link #noSortingRequired()} to avoid the overhead of sorting again.
 */

    private final ChildMap<FileSystemLocationSnapshot> children;
    private final HashCode contentHash;

    public DirectorySnapshot(String absolutePath, String name, AccessType accessType, HashCode contentHash, List<FileSystemLocationSnapshot> children) {
        this(absolutePath, name, accessType, contentHash, childMapFromSorted(children.stream()
            .map(it -> new ChildMap.Entry<>(it.getName(), it))

        verifyTaskDetails(RegisterTaskBuildOperationType, withPath(':', ':foo')).children.empty
        def realize = verifyTaskDetails(RealizeTaskBuildOperationType, withPath(':', ':foo'))
        realize.children.size() == 1
        def configure = realize.children[0]
        configure.children.size() == 1
        buildOperations.isType(configure.children[0], RealizeTaskBuildOperationType)

            displayName == 'Notify beforeEvaluate listeners of :foo'
            children*.displayName == ["Execute Project.beforeEvaluate listener"]
            children.first().children*.displayName == ["Apply script '${relativePath('foo/before.gradle')}' to project ':foo'"]
            parentId == configOp.id
        }

			ci := tst.children[i]
			ciRange := ci.timeRange()
			for j := i + 1; j < len(tst.children); j++ {
				cj := tst.children[j]
				cjRange := cj.timeRange()
				if ciRange.overlaps(cjRange) {
					return fmt.Errorf("test %s: child %s[%s] overlaps with child %s[%s]",
						tst.name, ci.name, ciRange, cj.name, cjRange)
				}
			}
		}
	}

	// Now check the children.

    private final List<T> children;

    public CompositeOperation(Iterable<? extends T> children) {
        this.children = Lists.newArrayList(children);
    }

    public List<T> getOperations() {
        return children;
    }

    @Override
    public Iterator<T> iterator() {
        return children.iterator();
    }

    @Override
    long getElapsedTime() {

      val children = node.children!!
      var child = children[childIndex]
      if (child == null) {
        child = Node()
        children[childIndex] = child
      }
      node = child
    }

    val shift = 8 - accumulatorBitCount
    val start = (code shl shift) and 0xff
    val end = 1 shl shift
    node.children!!.fill(terminal, start, start + end)
  }

        if (children == null) {
            children = new HashSet<ProgressOperation>();
        }
        return children.add(operation);
    }

    public boolean removeChild(ProgressOperation operation) {
        if (children == null) {
            throw new IllegalStateException(String.format("Cannot remove child operation [%s] from operation with no children [%s]", operation, this));
        }

		}

		if pcok {
			pc.mu.Lock()
			if len(pc.children) != 1 || !contains(pc.children, cc) {
				t.Errorf("bad linkage: pc.children = %v, cc = %v", pc.children, cc)
			}
			pc.mu.Unlock()
		}

		cancel()

		if pcok {
			pc.mu.Lock()
			if len(pc.children) != 0 {
				t.Errorf("child's cancel didn't remove self from pc.children = %v", pc.children)
			}
			pc.mu.Unlock()
		}

        elementOrFailure {
            val children = tree.children(node)

            var identifier: Syntactic<String>? = null
            var expression: CheckedResult<ElementResult<Expr>>? = null
            children.forEach {
                when (val tokenType = it.tokenType) {
                    MODIFIER_LIST -> {
                        val modifiers = tree.children(it)
                        modifiers.forEach { modifier ->