Module memory 

Concrete tier implementations + memory factories (M4.B 2026-05-10).

Three generic structs back the three tier sub-traits:

• SnapshotStorage<B, T, C> → SnapshotStorageTier<T>
• AppendLogStorage<B, T, C> → AppendLogStorageTier<T>
• KvStorage<B, T, C> → KvStorageTier<T>

Each holds:

• backend: Arc<B> (shared, multi-tier-share-one-backend supported per D147)
• codec: C (default JsonCodec per D148)
• name: String, debounce_ms, compact_every — cadence knobs
• filter, key_of — optional closures (boxed dyn Fn per D149)
• Internal pending buffer (parking_lot::Mutex’d)

Convenience factories memory_snapshot() / memory_append_log() / memory_kv() wrap a fresh in-process backend.

Structs

AppendLogStorage

Append-log tier — buffers per-key entries; flush() encodes each bucket as an array via codec and merge-writes it into the backend. Mirrors TS appendLogStorage.

AppendLogStorageOptions

KvStorage

Key-value tier — buffers per-key pending writes; flush() encodes each value via codec and writes it to the backend. Mirrors TS kvStorage.

KvStorageOptions

SnapshotStorage

Snapshot tier — buffers one pending snapshot; flush() encodes via codec and writes to the backend under key_of(snapshot). Mirrors TS snapshotStorage(backend, opts).

SnapshotStorageOptions

Options for SnapshotStorage construction.

Functions

append_log_storage

Factory: wrap a backend as an append-log tier.

kv_storage

Factory: wrap a backend as a kv tier.

memory_append_log

memory_kv

memory_snapshot

Convenience: snapshot tier over a fresh in-memory backend.

snapshot_storage

Factory: wrap a backend as a snapshot tier.