The Foreign Memory Access API should provide a common interface for all entities that can be mapped onto a MemoryAddress such as:

- MemoryAddress (trivially)
- MemorySegment (baseAddress)
- Lookup symbol
- VaList

This will give jextract more ammo to generate Addressable where a pointer is expected, so that clients can pass either a MemoryAddress or a MemorySegment, or a VaList.