Are you sure that the keys of entities in Added state have been set?

According to the documentation,


keys are set as soon as entities are tracked by the context, even if the entity is in the `Added` state.

In the following code, I found the claim is not correct.
Right before `SaveChangeAsync()` is invoked but after `AddAsync()` is invoked, the entity is in `Added` state and the `IsKeySet` is `False` (rather than `True` as the documentation claims). It means the key has not been set yet.

```csharp
private static async Task Add(StudentEnrollmentDbContext ctx, Course course, ILogger logger)
{
var added = await ctx.Courses.AddAsync(course);
logger.LogError(added.Entity.Id.ToString()); // output: 0
logger.LogError(added.State.ToString()); // output: Added
logger.LogError(added.IsKeySet.ToString()); // output: False
await ctx.SaveChangesAsync();
logger.LogError("=========================");
logger.LogError(added.Entity.Id.ToString()); // output: 1006
logger.LogError(added.State.ToString()); // output: Unchanged
logger.LogError(added.IsKeySet.ToString()); // output: True
return Results.CreatedAtRoute(nameof(Get), new { id = added.Entity.Id }, added.Entity);
}
```


---
#### Document Details

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* ID: b9826f28-46b2-e845-f1bf-5cbc2d940208
* Version Independent ID: 9c4a46cf-daa2-0e14-7ff1-c195db237cd0
* Content: [Disconnected Entities - EF Core](https://docs.microsoft.com/en-us/ef/core/saving/disconnected-entities)
* Content Source: [entity-framework/core/saving/disconnected-entities.md](https://github.com/dotnet/EntityFramework.Docs/blob/main/entity-framework/core/saving/disconnected-entities.md)
* Product: **entity-framework**
* Technology: **entity-framework-core**
* GitHub Login: @ajcvickers
* Microsoft Alias: **avickers**