Function attach_snapshot_storage 

pub fn attach_snapshot_storage(
    core: &Core,
    graph: &Graph,
    pairs: Vec<AttachTierPair>,
    options: AttachOptions,
) -> StorageHandle

Wire an observe subscription on graph that persists node changes to the provided snapshot+WAL tier pairs.

Debounce (D171, resolved 2026-05-14)

When a tier’s debounce_ms is Some(ms) with ms > 0, the observe callback writes via the tier’s save() (which buffers internally per the BaseStorageTier contract) but does NOT force a flush(). Callers drain pending writes by invoking StorageHandle::flush_all — typically from a binding-side reactive timer (e.g., graphrefly_operators::temporal::interval). This keeps graphrefly-storage sync + binding-agnostic per the canonical no-async-in-storage invariant; reactive-timer wiring lives in the layer that already owns the timer primitive.

When debounce_ms is None or Some(0), the observe callback continues to force-flush inline as before.

key_of (D174, closes F8)

The snapshot tier’s backend key is derived from graph.name via the checkpoint record’s name field. Cross-impl key_of divergence disappears at this boundary. D246: the embedder owns the Core (see graphrefly_core::OwnedCore) and passes &Core in — the observe_all_reactive subscription is opened owner-side. Teardown is owner-invoked via StorageHandle::detach (no RAII Drop, D246 r3).