References not eagerly fetched are lost

If you don't explicitly ask for related entities when you load an entity, you won't be able to do it later.

Problem

Object-Relational Mappers (ORMs) typically have a feature called lazy loading. Lazy loading means that when an entity is loaded from the database, all its relations (one-to-one, one-to-many, many-to-one, many-to-many) do not necessarily need to be loaded too. When they are first accessed, the ORM will issue a query and retrieve the records. This is interesting, because we do not need to pay the extra cost of loading potentially a lot of records if we are not going to use them. On the other hand, it requires that a connection is always available when the lazy properties are first accessed, otherwise their data cannot be retrieved.

So, here's the catch: Entity Framework Core 1.0 does not have lazy loading. It will come in a future version. What happens, then? Let's imagine we have the following class model:

using System...