TransformMany with IObservableCache

[John-MartinMalone]

I'd like to request an overload of TransformMany that works with child instances of IObservableCache

Something like this:

public static IObservable<IChangeSet<TDestination, TDestinationKey>> MyTransformMany<TDestination, TDestinationKey, TSource, TSourceKey>(this IObservable<IChangeSet<TSource, TSourceKey>> source, Func<TSource, IObservableCache<TDestination, TDestinationKey>> manySelector, Func<TDestination, TDestinationKey> keySelector)
        where TSourceKey : notnull
        where TDestinationKey : notnull
    {
        return new TransformMany<TDestination, TDestinationKey, TSource, TSourceKey>(source, manySelector, keySelector).Run();
    }

with an additional constructor in the TransformMany class:

public TransformMany(IObservable<IChangeSet<TSource, TSourceKey>> source, Func<TSource, IObservableCache<TDestination, TDestinationKey>> manySelector, Func<TDestination, TDestinationKey> keySelector) : 
        this(source, 
            x => manySelector(x).Items,
            keySelector, 
            t => Observable.Defer(
                () =>
                {
                    var subsequentChanges = Observable.Create<IChangeSet<TDestination, TDestinationKey>>(o => manySelector(t).Connect().Subscribe(o));

                    if (manySelector(t).Count > 0)
                    {
                        return subsequentChanges;
                    }

                    return Observable.Return(ChangeSet<TDestination, TDestinationKey>.Empty).Concat(subsequentChanges);
                }))
    {
    }

[RolandPheasant]

A PR would be welcome

[John-MartinMalone]

Submitted as #689

[John-MartinMalone]

A PR would be welcome

Any chance of getting it merged?

[RolandPheasant]

Could you add a description in the PR please.

[John-MartinMalone]

I've added a very brief description. Let me know if you need something more