Free Drive START events have always null location

Follow up ticket from https://github.com/mapbox/mapbox-navigation-android/pull/3791#issuecomment-729733263

From my tests START events never have location (is always null) 😞

We should check when the locationsCollector observer is registered because maybe trip session doesn't provide a location until the session is started but when it is started we immediately send event. The issue may be fixed if we do it after registering 🤔

cc @korshaknn

2020-11-18 11:29:20.995 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: Valid initialization
2020-11-18 11:29:43.459 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: session state is FREE_DRIVE
2020-11-18 11:29:43.459 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: sessionStop
2020-11-18 11:29:43.459 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: resetOriginalRoute
2020-11-18 11:29:43.459 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: resetRouteProgress
2020-11-18 11:29:43.459 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: trackFreeDrive START
2020-11-18 11:29:43.460 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: createFreeDriveEvent START
2020-11-18 11:29:43.476 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: populateFreeDriveEvent
2020-11-18 11:29:43.477 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: class com.mapbox.navigation.core.telemetry.events.NavigationFreeDriveEvent event sent
2020-11-18 11:29:43.504 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: Lifecycle monitor created
2020-11-18 11:29:43.509 25573-25573/com.mapbox.navigation.examples D/MAPBOX_TELEMETRY: onRawLocationChanged

onRawLocation is received after onNavigationSessionStateChanged when the event has been already sent.

override fun start() {
       if (state == TripSessionState.STARTED) {
           return
       }
       tripService.startService()
       startLocationUpdates()
       state = TripSessionState.STARTED
   }

startLocationUpdates is async and state executes the onSessionStateChanged right away before onRawLocationChanged.

We should investigate a different way to wait for the first location https://github.com/mapbox/mapbox-navigation-android/pull/3751#discussion_r521379048 and also discuss what to do if a session is started and no locations are received. Refs. https://github.com/mapbox/mapbox-navigation-android/issues/2827

cc @korshaknn @kmadsen @LukasPaczos

cc @korshaknn @kmadsen @LukasPaczos

Inizia con il flusso start() di TripSession, in particolare startLocationUpdates(), e traccia quando vengono recapitati onNavigationSessionStateChanged e onRawLocationChanged. Riproduci un evento FREE_DRIVE START e verifica se la prima posizione arriva dopo l’invio dell’evento. Il lavoro è completato quando è stato deciso e testato come START gestisce la prima posizione, incluso il caso in cui non venga ricevuta alcuna posizione.