If you're using Reactive (RX), why not use PRISM with ReactiveUI? http://reactiveui.net/ I use ReactiveUI + PRISM for software that I develop for work. If you use IObserver or IObservable, why not consider using a framework built around that? Reactive has mechanisms built in that handle updates via the IObservable / IObserver pattern.
To answer your question, you may want to use https://msdn.microsoft.com/en-us/library/system.reactive.linq.observable.throttle%28v=vs.103%29.aspx Throttle, as it is designed to throttle the number of updates. Linq for RX is very powerful.
To answer your question, you may want to use https://msdn.microsoft.com/en-us/library/system.reactive.linq.observable.throttle%28v=vs.103%29.aspx Throttle, as it is designed to throttle the number of updates. Linq for RX is very powerful.