fn process_control_msg(
    reader: &mut Reader,
    ports: &[WorkerPort],
    pending_receive_control_msgs: &mut VecDeque<ControlMsgBytes>,
) -> Result<()>fn process_control_msg(
    reader: &mut Reader,
    ports: &[WorkerPort],
    pending_receive_control_msgs: &mut VecDeque<ControlMsgBytes>,
) -> Result<()>