ReactiveUI and Rx background calculations with cancellation
When Switch unsubscribes from the previous Observable to connect to the new one, FromAsync should signal the cancellation token and also correctly eat the ThrowOnCancellation exception. 

While it'd probably be better to try to use a ReactiveCommand to model the loading bool (which might not be easy given the cancelation and Switch), if this code works for you it should be fine.

Make sure to specify RxApp.MainThreadScheduler for the Throttle though, it's more efficient