cancelChild, stop := WithCancel(parent)
	defer stop()
	valueChild := WithValue(parent, "key", "value")
	timerChild, stop := WithTimeout(valueChild, veryLongDuration)
	defer stop()
	afterStop := AfterFunc(parent, func() {})
	defer afterStop()

	select {
	case x := <-parent.Done():
		t.Errorf("<-parent.Done() == %v want nothing (it should block)", x)
	case x := <-cancelChild.Done():

absl::flat_hash_set<Operation*> GetMoveOpsBetweenTwoIfRegions(
    Operation* result_op, Operation* after_op,
    llvm::SmallSetVector<Operation*, 4> middle_if_ops,
    const std::unique_ptr<TF::SideEffectAnalysis>& side_effect_analysis) {
  Block* block = after_op->getBlock();
  std::queue<Operation*> queue;
  absl::flat_hash_set<Operation*> visited;
  absl::flat_hash_set<Operation*> moved_ops;

  if (!external_operands.empty()) host_ops.push_back(recv_at_host);
  Operation* after_op = recv_at_host;
  for (Operation* cluster_op : clustered_ops) {
    cluster_op->moveAfter(after_op);
    cluster_op->removeAttr(StringAttr::get(op.getContext(), kDeviceAttr));
    after_op = cluster_op;
    host_ops.push_back(cluster_op);
  }

  if (!external_outputs.empty()) {