/// <summary>
/// create an observable for animating multiple related values at once
/// </summary>
/// <param name="fromValues">the observable values to animate from</param>
/// <param name="toValues">the observable values to animate to</param>
/// <returns>observable animation progress for subscription and updating the target object</returns>
public IObservable <IEnumerable <AnimationProgress> > CreateObservable(IObservable <IEnumerable <AnimatableValue> > fromValues, IObservable <IEnumerable <AnimatableValue> > toValues)
{
return(Progress.CombineLatest(fromValues.DistinctUntilChanged(), toValues.DistinctUntilChanged(),
(p, f, t) => f.Join(t, fv => fv.Key, tv => tv.Key,
(fv, tv) => new AnimationProgress
{
Key = fv.Key,
FromValue = fv.Value,
ToValue = tv.Value,
Progress = p
})));
}