[Rx]Event rate smoothing operator called "StepInterval"

gistfile1.cs

//Source: http://stackoverflow.com/a/11285920/3244
public static IObservable<T> StepInterval<T>(this IObservable<T> source, TimeSpan minDelay)
{
    return source.Select(x => 
        Observable.Empty<T>()
            .Delay(minDelay)
            .StartWith(x)
    ).Concat();
}