Scope

data class Scope(val ownerId: String? = null, val spaceId: String? = null)

An owner and a space, together: who an aggregate belongs to. One value type serves commands, event streams, snapshots and query authorization, and where it sits says what it means: on a command it is the caller's scope that admission decided; on an event stream or a snapshot it is the aggregate's own, after that commit.

Either part may be absent; a present one is not blank.