Currently WindowAttributess purpose is to expose the current state of WindowBuilder. But it doesn't support platform-specific fields.
It would be nice to move PlatformSpecificWindowBuilderAttributes into WindowAttributes so we can do that.

Alternatively, I'm not entirely sure why WindowAttributes exists in the first place if seemingly we could let users just get free (mutable) access to WindowBuilder fields and the ones we don't want them to get access to can have getters/setters.

What do you guys think?