When using document-based storage, allow projecting certain properties to columns

[kzu]

This could be handy to allow querying by those columns in particular.

So maybe it could be via an implemented interface that's then used when creating the repository? For example: DocumentRepository.Create<Book, IAddressable>()?

        public static IDocumentRepository<T> Create<T, TProperties>(...)
            where T: class, TProperties
            where TProperties: IDocumentEntity

Where the returned document repository augmented IDocumentRepository<T> with the ability to perform queries, such as:

        public interface IDocumentRepository<T, TProperties> : IDocumentRepository<T>
            where T : class, TProperties
        {
            IAsyncEnumerable<T> CreateQuery(Expression<Func<TProperties, bool>> predicate, CancellationToken cancellation = default);
        }

Note that unlike table repository IQueryable<T> CreateQuery() version, we need to restrict the available properties for querying to the TProperties since not all T properties will be available as columns. So using an expression for the properties and an async enumerable with the full entity type seems the most natural.