Example throws "Expected version not set" error

[yaguiman72]

Hi, excelent example to dig in in the world of CQRS, EventSourcing and EventStoredDB.
I'm trying to execute the C# EventStoreDB Ecommerce example and I couldn't add a product to the cart because I always get the error "Expected version not set" because expectedStreamRevisionProvider.Value is null, even after I created a cart.

Is it something wrong with the source code?
Does ExpectedResourceVersionProvider is working in the example?

Thanks and regards,
Martin