Function spawn_reader_task 

pub(crate) fn spawn_reader_task(
    subprocess: Subprocess,
    dispatch: ControlDispatchHandle,
    pending_controls: Arc<Mutex<HashMap<String, Sender<Result<Value, Error>>>>>,
    events_tx: UnboundedSender<Result<Message, Error>>,
    pre_init_messages: Vec<Message>,
    shutdown_rx: Receiver<()>,
) -> JoinHandle<()> 

Spawn the post-init reader task.

Pre-pumps pre_init_messages into events_tx first, then runs the main read loop. On shutdown signal (or EOF / I/O error / closed events channel), closes the transport and drains pending controls with an EOF error so blocked send_control callers wake up.