CacheObservable<T> for UniRx

    class CacheObservable<T> : OperatorObservableBase<IList<T>>
    {
        readonly UniRx.IObservable<T> source;
        readonly int count;

        public CacheObservable(UniRx.IObservable<T> source, int count)
            : base(source.IsRequiredSubscribeOnCurrentThread())
        {
            this.source = source;
            this.count = count;
        }

        protected override IDisposable SubscribeCore(UniRx.IObserver<IList<T>> observer, IDisposable cancel)
        {
            return new CacheImpl(this, observer, cancel).Run();
        }


        // count only
        class CacheImpl : OperatorObserverBase<T, IList<T>>
        {
            readonly CacheObservable<T> parent;
            List<T> list;

            public CacheImpl(CacheObservable<T> parent, UniRx.IObserver<IList<T>> observer, IDisposable cancel) : base(
                observer, cancel)
            {
                this.parent = parent;
            }

            public IDisposable Run()
            {
                list = new List<T>(parent.count);
                return parent.source.Subscribe(this);
            }

            public override void OnNext(T value)
            {
                list.Add(value);
                if (list.Count == parent.count)
                {
                    observer.OnNext(list);
                    list.RemoveAt(0);
                }
            }

            public override void OnError(Exception error)
            {
                try
                {
                    observer.OnError(error);
                }
                finally
                {
                    Dispose();
                }
            }

            public override void OnCompleted()
            {
                if (list.Count > 0)
                {
                    observer.OnNext(list);
                }

                try
                {
                    observer.OnCompleted();
                }
                finally
                {
                    Dispose();
                }
            }
        }
    }