What is CodableWithConfiguration used for?

Hi,

I noticed the CodableWithConfiguration protocol in the section of the talk about AttributedString. I'm not really sure what purpose it serves and how it fits in with the original Codable protocol.

As far as I can tell there aren't (as of beta 3) any ways to decode/encode objects conforming to this protocol with JSONDecoder/PropertyListDecoder/TopLevelDecoder. I expected there to be something like JSONDecoder().decode(_:from:configuration:) to match the existing JSONDecoder().decode(_:from:). It looks like only the keyed and un-keyed coding containers (but not single value containers) provide ways to decode/encode such objects.

I guess my questions are:

• What are the use cases for these new protocols?
• Is the configuration object designed to replace the userInfo dictionary on Decoder/Encoder?
• If I currently pass required information to decoders/encoders via this userInfo dictionary, should I consider using CodableWithConfiguration to avoid typecasting from Any?
• Why is support for decoding/encoding these objects so limited compared with the original Codable protocols?

Thanks!