// mean cancel won't be called if this Future is passed into setFuture, and then
  // cancelled.
  private static final class InCompletionOrderFuture<T extends @Nullable Object>
      extends AbstractFuture<T> {
    private @Nullable InCompletionOrderState<T> state;

    private InCompletionOrderFuture(InCompletionOrderState<T> state) {
      this.state = state;
    }

    @Override