Unity/UniRx/値変更検知

IsCompletedが、trueになったときに、検知

hoge.ObserveEveryValueChanged(x => x.IsCompleted)
                .Subscribe(isCompleted =>
                {
                    if (!isCompleted) return;
                    Debug.Log("isCompleted =" + isCompleted);
                    Debug.Log("hoge.IsCompleted=" + hoge.IsCompleted); 
                })
                .AddTo(gameObject);