pub const fn mix64(a: u64, b: u64) -> u64Expand description
2026-09-25: The splitmix64 finalizer over a ^ b * GOLDEN.
The fold behind the persisted wire keys: model-engine’s
PagingSnapshotStore::wire(key) is mix64(key, namespace), and the decode
namespace folds mix64(fingerprint, DECODE_DOMAIN) with the client salt.
A change to it changes every stored key.