Function spawn 

pub fn spawn(
    config: SysmonConfig,
    component: Arc<RwLock<Component>>,
    observer: Arc<dyn RunObserver>,
) -> Result<JoinHandle<()>, String>

Spawn the sampler. check_rambw_requirements must have passed first — the runner aborts the session on its Err rather than calling this. Runs until session shutdown; publishes each window to the session gauges and to observer.sysmon_update.