pub fn valkey_kind(err: &EngineError) -> Option<ErrorKind>Expand description
Returns the underlying ferriskey ErrorKind if err maps back
to a transport-level fault whose inner source is a ScriptError.
Postgres-backed or other non-Valkey transport errors return None.
Issue #171: gated behind valkey-client (default-on) so the
ferriskey dep stays optional for alternate-backend consumers.