Sink an export streams entries into, so one async loop drives folder/zip/xz writes. Archive sinks work on every target; the folder sink and `write_entry_from_path` are native-only. `Send` because `stream_entries` holds `&mut dyn ExportSink` across `.await`s.
source not stored for this graph (policy: none)
nothing calls this directly
no outgoing calls
no test coverage detected