Both RxJS and Rx .NET implement DelaySubscription: - [`Rx.Observable.prototype.delaySubscription`](https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/delaysubscription.md) - [`Observable.DelaySubscription(TimeSpan dueTime, IScheduler scheduler)`](https://github.com/Reactive-Extensions/Rx.NET/blob/master/Rx.NET/Source/System.Reactive.Linq/Reactive/Linq/Observable.Time.cs#L393-L448) - [`Observable.DelaySubscription(DateTimeOffset dueTime, IScheduler scheduler)`](https://github.com/Reactive-Extensions/Rx.NET/blob/master/Rx.NET/Source/System.Reactive.Linq/Reactive/Linq/Observable.Time.cs#L450-L499)
