Support Custom ID Generators

[adrianotr]

Problem

Currently different types of Guid are supported, such as

• Guid.NewGuid()
• MassTransit.NewId
• GuidComb

There's also this open issue to support Ulid.
At some point UUID v7 and v8 specs will likely need to be included.

Solution

I think it might be great if we could have a more relaxed approach to generating ids.

Something like this:

// Id type
[Strongly(newIdGenerator: typeof(MyCustomIdGenerator))]
public readonly partial struct SomeId;

// Id generator
public static class MyCustomIdGenerator
{
    public static Guid New() => NewId.NextSequentialGuid();
}

Th generated code can use the fully qualified name of MyCustomIdGenerator to call the static method New().

public static TYPENAME New() => new TYPENAME(MyProject.MyCustomIdGenerator.New());

This way the id can be generated in whatever way it's needed, no need to create a new Id type for each possible case.