get
  suspend fun OrsClient.getRouteGpx(start: Pair<Double, Double>, end: Pair<Double, Double>, profile: String): String
Retrieves a route as GPX between two coordinates.
suspend fun OrsClient.getRouteGpx(coordinates: List<List<Double>>, language: String, profile: String): String
Retrieves a route as GPX for an arbitrary coordinate list.