The pieces were tested one at a time, so removing the one line in `_build_node` that wraps a worker-backed function with its sink broke nothing visible — while losing every generator node's last yield and returning None in its place.
The pieces were tested one at a time, so removing the one line in `_build_node` that wraps a worker-backed function with its sink broke nothing visible — while losing every generator node's last yield and returning None in its place.