Key

Represents a discriminator strategy where the subtype identifier is encoded as the key of a TOON record.

It is a default strategy for serializing and deserializing of all kinds of variants (sealed hierarchies, union types, etc.).

In this strategy, the serialized representation of the subtype wraps the encoded value in a nested record keyed by the subtype's discriminator, e.g., SubtypeIdentifier: followed by indented fields.

This approach enables subtype differentiation based solely on the key of the TOON record for the sealed hierarchy.