Why are methods Observable.While and Observable.Prune in the Microsoft.Phone.Reactive namespace?

Question

I noticed that the Observable.While and Observable.Prune methods are part of the Microsoft.Phone.Reactive namespace. Just curious as to why this is given these methods should be applicable to all OS?

Answer 1

With the April 2011 version of Rx there have been some changes, to get Prune use TakeLast(1), to get While use TakeWhile. These changes are not in the windows phone version yet as it uses a separate version as explained here.