granular (default): subscribers apply the delivered ChangeMessage[]
deltas to their own keyed state (Vue/Svelte/Solid). The observer
subscribes with initial state and seeds late subscribers, so every
subscriber converges from deltas alone.
wholesale: subscribers treat notifications as a wake-up and re-read
getSnapshot() (React/Angular). The observer subscribes WITHOUT initial
state, preserving those adapters' loading policy — no snapshot request,
so no unfiltered loadSubset against on-demand collections. Nothing is
delivered synchronously during subscribe, which keeps
useSyncExternalStore-style consumers safe by construction.