Future<void> _getDistance(PlacesDetailsResponse start,
      PlacesDetailsResponse end,) async {
    List<Location> origin = [
      start.result.geometry.location,
    ];
    List<Location> destination = [
      end.result.geometry.location,
    ];

    GoogleDistanceMatrix distanceMatrix =
    new GoogleDistanceMatrix(apiKey: kGoogleApiKey);

    DistanceResponse response = await distanceMatrix.distanceWithLocation(
      origin,
      destination,
    );

    try {
      if (response.isOkay) {
        response.results.forEach((row) {
          row.elements.forEach((element) {
            distance = element.distance;
            duration = element.duration;
          });
        });
      } else {
        print('ERROR: ${response.errorMessage}');
        Future.error(Error());
      }
    } finally {
      distanceMatrix.dispose();
    }
  }