patch
open suspend override fun patch(key: String, payload: ByteArray, maxAgeMs: Long?, tags: Set<String>?)
PATCH-style write. Replaces the payload of key but preserves maxAgeMs and tags when their argument is null.
Semantics per parameter:
maxAgeMs = null→ keep existing entry's TTL.0→ no explicit expiry.>0→ use it.tags = null→ keep existing entry's tags.emptySet()→ explicitly clear. Non-empty → replace.
The createdAt timestamp resets — a patch is a new write, freshness window restarts. If key has no existing entry, falls back to: maxAgeMs = 0, tags = emptySet().