public void Subscribe(ICompletableObserver observer)
        {
            var parent = new DelaySubscriptionObserver(observer, source);

            observer.OnSubscribe(parent);
            other.Subscribe(parent);
        }
        public void Subscribe(IMaybeObserver <T> observer)
        {
            var parent = new DelaySubscriptionObserver(observer, source);

            observer.OnSubscribe(parent);
            other.Subscribe(parent);
        }
        public void Subscribe(ICompletableObserver observer)
        {
            var parent = new DelaySubscriptionObserver(observer, source);

            observer.OnSubscribe(parent);

            parent.SetTask(scheduler.Schedule(parent, delay, RUN));
        }