pub fn write_section_frame_shapes(shapes: &[FrameShapeDef], buf: &mut Vec<u8>)Expand description
Write the FS-3 FrameShapes section (no header framing): a one-byte
section-local version, then one entry per await site
(docs/flow-suspension-spec.md §4/§11) — the site’s stable DefinitionId
(the synthesized continuation container id) followed by its name-keyed
crossing-local slots. Entries are written in the order given; callers sort
by site for determinism. Callers emit this section only when non-empty.