MapPageViewModel.cs

namespace UberClone.ViewModels
{
    public class MapPageViewModel : INotifyPropertyChanged
    {
        ...
        public MapPageViewModel()
        {
            var _stateMachine = new StateMachine<XUberState, XUberTrigger>(XUberState.Initial);

            CalculateRouteTrigger = _stateMachine.SetTriggerParameters<GooglePlaceAutoCompletePrediction>(XUberTrigger.CalculateRoute);

            _stateMachine.Configure(XUberState.Initial)
                .OnEntry(Initialize)
                .OnExit(() => { Places = new ObservableCollection<GooglePlaceAutoCompletePrediction>(RecentPlaces); })
                .OnActivateAsync(GetActualUserLocation)
                .Permit(XUberTrigger.ChooseDestination, XUberState.SearchingDestination)
                .Permit(XUberTrigger.CalculateRoute, XUberState.CalculatingRoute); 

            _stateMachine
                .Configure(XUberState.SearchingOrigin)
                .Permit(XUberTrigger.Cancel, XUberState.Initial)
                .Permit(XUberTrigger.ChooseDestination, XUberState.SearchingDestination);

            _stateMachine
                .Configure(XUberState.SearchingDestination)
                .Permit(XUberTrigger.Cancel, XUberState.Initial)
                .Permit(XUberTrigger.ChooseOrigin, XUberState.SearchingOrigin)
                .PermitIf(XUberTrigger.CalculateRoute, XUberState.CalculatingRoute, () => OriginCoordinates != null);

            _stateMachine
              .Configure(XUberState.CalculatingRoute)
              .OnEntryFromAsync(CalculateRouteTrigger, GetPlacesDetail)
              .Permit(XUberTrigger.ChooseRide, XUberState.ChoosingRide)
              .Permit(XUberTrigger.Cancel, XUberState.Initial); 

            _stateMachine
               .Configure(XUberState.ChoosingRide)
               .Permit(XUberTrigger.Cancel, XUberState.Initial)
               .Permit(XUberTrigger.ChooseDestination, XUberState.SearchingDestination)
               .Permit(XUberTrigger.ConfirmPickUp, XUberState.ConfirmingPickUp);

            _stateMachine
              .Configure(XUberState.ConfirmingPickUp)
              .Permit(XUberTrigger.ChooseRide, XUberState.ChoosingRide)
              .Permit(XUberTrigger.ShowXUberPass, XUberState.ShowingXUberPass);

            _stateMachine
              .Configure(XUberState.ShowingXUberPass)
              .Permit(XUberTrigger.ConfirmPickUp, XUberState.ConfirmingPickUp)
              .Permit(XUberTrigger.WaitForDriver, XUberState.WaitingForDriver);

            _stateMachine
             .Configure(XUberState.WaitingForDriver)
             .Permit(XUberTrigger.CancelTrip, XUberState.Initial)
             .Permit(XUberTrigger.StartTrip, XUberState.TripInProgress);
             
            State = _stateMachine.State;

            _stateMachine.ActivateAsync();
        }

        private void Initialize()
        {
            CleanPolylineCommand.Execute(null);
            DestinationLocation = string.Empty;
        }

        private async Task GetActualUserLocation()
        {
            try
            {
                await Task.Yield();
                var request = new GeolocationRequest(GeolocationAccuracy.High,TimeSpan.FromSeconds(5000));
                var location = await Geolocation.GetLocationAsync(request);

                if (location != null)
                {
                    OriginCoordinates = location;
                    CenterMapCommand.Execute(location);
                    GetLocationNameCommand.Execute(new Position(location.Latitude, location.Longitude));
                }
            }
            catch (Exception)
            {
                await UserDialogs.Instance.AlertAsync("Error", "Unable to get actual location", "Ok");
            }
        }
        ...
    }
}