Use case: I would like to associate subfolders stored in the Application Support Directory on iOS with already saved instances of a SwiftData entity type. If I had a way to represent the primary keys of the entities as a string, I could simply name these subfolders after the primary keys (without the need to generate e.g. random UUID folder names and persist these UUIDs as a field in the entity).

The PersistentIdentifier of SwiftData entities is a Codable Struct, which, when encoded with a JSONEncoder, looks like this:

{
  "implementation": {
    "uriRepresentation": "x-coredata://StoreID/EntityName/p123",
    "isTemporary": false,
    "primaryKey": "p123",
    "storeIdentifier": "StoreID",
    "entityName": "EntityName"
  }
}

Is this Codable representation regarded as a part of the public API of SwiftData, i.e. is it safe to use the primaryKey field in production in my use case?