* perf(signer): cache signing key to avoid redundant HMAC-SHA256
Cache the AWS4 signing key per (secret, region, date, service_type)
tuple. The signing key is derived from 4 HMAC-SHA256 calls and is
constant for a given user within the same UTC day, so caching it
eliminates ~0.5-1ms of redundant crypto per request.
The cache uses a LazyLock<Mutex<HashMap>> with automatic daily
rotation (cache entries naturally expire when the date component
of the key changes).
Refs: https://github.com/rustfs/backlog/issues/2005
Co-Authored-By: heihutu <[email protected]>
* fix(signer): bound signing key cache
* fix(signer): satisfy cache lint
---------
Co-authored-by: heihutu <[email protected]>
Co-authored-by: overtrue <[email protected]>
