ReadonlyattributionReadonlybytesCaller-owned bytes exactly as they were persisted; never re-encoded.
ReadonlycacheOptional ReadonlycontentReadonlydegradedSame never-silently-live discipline a Result carries, in the same
vocabulary. A binary read has no Result to stamp, so the degradation
travels here.
ReadonlykindReadonlyplanReadonlyprovenanceReadonlyregionReadonlyresourceReadonlyresourceReadonlytileReadonlyversion
A tile payload, plus the canonical coordinate that addressed it.