Module durability 

Durability trait — abstracts Bitcask (append-only log) and FixedStore (fixed-slot pwrite) backends behind a common interface.

DurabilityInner covers per-shard write operations (one locked shard). Durability covers engine-level operations (shard routing, open/close).

Concrete types:

• Bitcask / ShardInner — append-only log
• Fixed / FixedShardInner — fixed-slot pwrite

Structs

Bitcask

Engine-level wrapper for the Bitcask (append-only log) backend.

Fixed

Engine-level wrapper for the FixedStore (fixed-slot pwrite) backend.

Traits

Durability

Engine-level durability operations.

DurabilityInner

Per-shard write operations abstracted over storage backend.