insert deadtime between items

RxDeadTime.cs

static IObservable<T> DeadTime<T>(this IObservable<T> source, TimeSpan deadTime)
{
    return Observable.Create<T>(o =>
    {
        var subscriptions = new CompositeDisposable();
        var deadTimeTimer = new Subject<IObservable<long>>();
        var inDeadTime = false;
        subscriptions.Add(
            source.Subscribe(
                item =>
                {
                    if (!inDeadTime)
                    {
                        inDeadTime = true;
                        deadTimeTimer.OnNext(Observable.Timer(deadTime));
                        o.OnNext(item);
                    }
                },
                o.OnError,
                o.OnCompleted)
            );
        subscriptions.Add(
            deadTimeTimer
                .Switch()
                .Subscribe(_ => inDeadTime = false)
            );
        return subscriptions;
    });
}