INotifyPropertyChanged to Observable (portable FromPropertyChangedPattern)

INotifyPropertyChangedExtensions.cs

namespace Test
{
    public static class INotifyPropertyChangedExtensions
    {
        public static IObservable<EventPattern<PropertyChangedEventArgs>> FromPropertyChangedPattern(this INotifyPropertyChanged source)
        {
            return Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
                x => source.PropertyChanged += x,
                x => source.PropertyChanged -= x);
        }

        public static IObservable<EventPattern<PropertyChangedEventArgs>> WhenAnyPropertyChanges<T>(this T source, params Expression<Func<T, object>>[] properties)
            where T : INotifyPropertyChanged
        {
            return WhenAnyPropertyChanges(source, FromPropertyChangedPattern(source), properties);
        }

        public static IObservable<EventPattern<PropertyChangedEventArgs>> WhenAnyPropertyChanges<T>(this T source, IObservable<EventPattern<PropertyChangedEventArgs>> observable, params Expression<Func<T, object>>[] properties)
            where T : INotifyPropertyChanged
        {
            return WhenAnyPropertyChanges<T>(observable, properties);
        }

        public static IObservable<EventPattern<PropertyChangedEventArgs>> WhenAnyPropertyChanges<T>(this IObservable<EventPattern<PropertyChangedEventArgs>> source, params Expression<Func<T, object>>[] properties)
        {
            return WhenAnyPropertyEventOccurs(source, x => x.EventArgs.PropertyName, properties);
        }

        public static IObservable<TObservable> WhenAnyPropertyEventOccurs<T, TObservable>(this IObservable<TObservable> source, Func<TObservable, string> propertyNameSelector, params Expression<Func<T, object>>[] properties)
        {
            var propertyNames = properties
                .Select(x => x.Body)
                .OfType<MemberExpression>()
                .Select(x => x.Member.Name);

            return source
                .Where(x => propertyNames.Any(y => EqualityComparer<string>.Default.Equals(y, propertyNameSelector(x))));
        }
    }
}

Hi @patsissons. Any chance we could see usage of this somewhere? PArticularly WhenAnyPropertyChanges.