Function braid_triggerbox::launch_background_thread

pub fn launch_background_thread(
    callback: Box<dyn FnMut(Option<ClockModel>) + Send>, 
    device: String, 
    cmd: Receiver<Cmd>, 
    triggerbox_data_tx: Option<Sender<TriggerClockInfoRow>>, 
    query_dt: Duration, 
    assert_device_name: NameType
) -> Result<(Control, JoinHandle<()>)>