Module backend 

The LockBackend abstraction and its implementations.

A backend owns the authoritative lock state for a set of resource keys. The client / guard / watchdog layers are backend-agnostic and drive everything through this trait.

Implementations provided:

• InMemoryBackend — a fully working single-process backend (the default), and the target of the deterministic simulation test.
• etcd::EtcdBackend — real distributed locking over an etcd v3 cluster (leases + transactions, revision-based fencing tokens). Requires the etcd feature.

Structs

InMemoryBackend

A single-process, in-memory LockBackend.

Traits

LockBackend

Authoritative storage and arbitration for distributed locks.