CodingKeyRepresentable

With a CodingKeyRepresentable type, you can losslessly convert between a custom type and a CodingKey type.

Conforming a type to CodingKeyRepresentable lets you opt in to encoding and decoding Dictionary values keyed by the conforming type to and from a keyed container, rather than encoding and decoding the dictionary as an unkeyed container of alternating key-value pairs.