How do you use NodeGraphType to define an Interface

I would like to use `NodeGraphType` to implement the `NodeInterface` type. I'm trying to get my head around why `NodeGraphType` exists and how to use it. I think it:

1. Implements `Interface();` for you.
2. Implements the If field for you using `Id(x => x.Id)` instead of defining it yourself:

```
this.Field(x => x.Id, type: typeof(NonNullGraphType))
.Description("The unique identifier of the droid.");
```

3. Registers the type globally, so that given you implement `QueryGraphType`, lets you resolve any object globally by it's ID.

I've also found a few problems:

1. It assumes that the ID is of type string. Can I use a `System.Guid` instead?
2. The GetById is not async and does not accept a `CancellationToken`. Ideally it should have the signature:

```
Task GetById(T id, CancellationToken cancellationToken = default);
```

Where `T` is a generic type to allow you to specify the type of the ID. Allowing you to use a `Guid`.