Case 1 should return the snapshot, case 4 should not return the nulls, can you please double-ceck?

In any case you can't use a fixed value in the update call:

you have to return true in the IsSnapshotAvailable and then you have to use true on the first Update call following the subscription of the related item, and use false for every subsequent call until you get the unsubscription for the item. If there is a new subscription call you will repeat the same: true on the first Update false on the subsequent ones

This demo does that: https://github.com/Weswit/Lightstrea...dapter-dotnet/

https://github.com/Weswit/Lightstrea...ockList.cs#L62

https://github.com/Weswit/Lightstrea...ckList.cs#L102