Opaque cloned per-slice payload; the owning loader casts it back.
Total retained bytes (sum of the snapshot's typed-array byteLengths).
OptionalladderStored additive prefix depth, when the entry represents a ladder.
OptionaltotalTotal additive ladder depth for the node that produced this entry.
One cached per-slice entry.
payloadis opaque (the owning loader's cloned decoded-slice snapshot);bytesis the retained size the loader measured, used for LRU accounting.