Some really impressive work from my teammate Kevin here: https://forums.swift.org/t/the-future-of-serialization-deserialization-apis/78585
If you care about Codable and/or serialization in Swift in general, definitely check it out

The future of serialization & deserialization APIs
Hello Swift Community, I’m happy to announce that I've been hard at work planning a potential future for serialization & deserialization APIs in Swift. It's clear from community adoption and feedback that Codable has had a lot of success in the years since it was added to Swift 4, but that it doesn’t satisfy some important needs. One of the foremost of those needs is performance more in line with programming environments that compete with Swift. As such, the main goal for this effort is to unlo...