Unity/UniRx/Observable

Observable.Createを使う

Observable.Create<int>(observer =>
{
    for (var i = 1; i <= 3; i++)
    {
        observer.OnNext(i);
    }
    Debug.Log("Finished");
    observer.OnCompleted();
    return Disposable.Create(() =>
    {
        Debug.Log("Dispose");
    });
}).Subscribe(x => Debug.Log(x));

参考：https://qiita.com/toRisouP/items/86fea641982e6e16dac6