The async half of demand-driven geometry (Phase B): source-byte residency.
Extraction is synchronous by design (the wasm extract reads source bytes
through StepBufferProvider.acquire), but a windowed/streamed source pages
bytes in asynchronously (ensureResident). This pump owns that seam: it
admits demand, prefetches the source ranges for the most-wanted products,
and only then forwards them to the synchronous DemandGeometryQueue
— so a pump() never hits a non-resident range mid-extract.
The async half of demand-driven geometry (Phase B): source-byte residency.
Extraction is synchronous by design (the wasm extract reads source bytes through
StepBufferProvider.acquire), but a windowed/streamed source pages bytes in asynchronously (ensureResident). This pump owns that seam: it admits demand, prefetches the source ranges for the most-wanted products, and only then forwards them to the synchronous DemandGeometryQueue — so apump()never hits a non-resident range mid-extract.