private void FindNearestAirport()
        {
            var positionAsObservable =
                Observable.FromEvent <EventArgs <Location> >(
                    ev => _locationService.PositionAvailable += ev,
                    ev => _locationService.PositionAvailable -= ev);

            var locations = from e in positionAsObservable
                            select new Location(e.EventArgs.Content.Latitude,
                                                e.EventArgs.Content.Longitude);

            locations.Subscribe(l => Messenger.Default.Send(new AirportSelectedMessage(_airportsService.GetNearestAirport(l))));

            _locationService.GetPositionAsync();
        }