Function drain_and_publish 

async fn drain_and_publish(
    broker: &Broker,
    filestore: &FileStore,
    translator: Box<dyn Translator>,
    scope: &str,
    source_block_id: &str,
    request_id: &str,
    throwaway_block_id: &str,
)

Poll the throwaway block’s own output FileStore subject for newly appended stream-json lines, translate each into AgentEvents, and publish one EVENT_BTW_ANSWER_CHUNK per event on scope. Returns once a terminal event (Done/Error) has been published, or after synthesizing one on timeout / unexpected exit. See the module doc comment for why this polls FileStore directly instead of hooking into spawn_turn’s own output path.