ReadonlyetagReadonlydataReadonlyheadersReadonlytimestampWhen the entry was written, in milliseconds since the epoch.
Optional ReadonlyttlHow long the store keeps the entry, in milliseconds, when not the store's
default. This is retention, not freshness: the pipeline passes the
response's freshness plus a stale-retention window, so the body stays
available for If-None-Match revalidation and stale-on-error after it
stops being fresh. A store drops the entry only once this has passed.
Where conditional-request caching keeps response bodies and their ETags, keyed by request URL.
ETagCacheManageris the in-memory implementation; a shared store (Redis, a file) implements the same five calls.