How to delay one of two signals but discard it if necessary? - xamarin.forms

Question

I use ReactiveUI and Prism in my Xamarin.Forms application.
Prism, on one side controls the page appear/disappear signal and sends the disappear event just before the view-navigation animation starts.
ReactiveUI on the other side offers a view.WhenActivated(...) extension to only establish view-bindings when the view is shown. The view.WhenActivated() gets disposed when the disappear event is fired.
Since Prism is sending the disappear event while the view-to-unload is still shown, the view bindings gets dissolved in front of the customers eyes.
To prevent this I tried to register my own copy of ReactiveUI's implementation of IActivationForViewFetcher (ReactiveUI.XamForms.ActivationForViewFetcher) and delay the disappear event just as long as the animation isn't over yet (1 second).
var appearing = Observable.FromEvent<EventHandler, bool>(
eventHandler =>
{
void handler(object sender, EventArgs e) => eventHandler(true);
return handler;
},
x => page.Appearing += x,
x => page.Appearing -= x)
// timestamp the event for later take-last scan
.Timestamp();
var disappearing = Observable.FromEvent<EventHandler, bool>(
eventHandler =>
{
void handler(object sender, EventArgs e) => eventHandler(false);
return handler;
},
x => page.Disappearing += x,
x => page.Disappearing -= x)
// timestamp the event for later take-last scan
.Timestamp()
// slow-down the disappearing event to avoid visual un-binding effects
// like re-enabled buttons, values unset and so on.
.Throttle(TimeSpan.FromSeconds(1))
.ObserveOn(RxApp.MainThreadScheduler);
return Observable
.Merge(appearing, disappearing)
.Scan(new Timestamped<bool>(false, DateTimeOffset.MinValue),
(last, n) => n.Timestamp >= last.Timestamp ? n : last)
.Select(v => v.Value)
.DistinctUntilChanged();
This works well in case the user is slow but for some scenarios the disappear-delay may render the active page as deactivated.
Now to my question:
Is there a easier way to delay the disappear signal but avoid it as a whole just in case the page was re-activated in the delay-window?
A bit more information: the appear and disappear events may be triggered by the frameworks more than once so that a de/activated page may be de/activated again without effect.
Thanks