vertexBuffer

Interleaved VBO resolved fresh from the RR cache at enqueue time. Matches the drawable-enqueue resolution pattern used by DrawableTileMesh / Path / Polygon / OSM Buildings — keeping the ref on the drawable instead of on PointCloudContent means a cache eviction between frames surfaces as a null slot here (skipping the draw) rather than a stale BufferObject.id bind on a content-cached ref.