Show MKPolyline on top of MapView when type is SatelliteFlyover?

问题

I want to show a few MKPolylines on top of MapKit's mapView. The problem is when setting the map type to .satelliteFlyover my polylines will disappear. If I change to just using .satellite they're visible.

mapView.type = .satelliteFlyover
mapView.addOverlay(polyline)

来源：https://stackoverflow.com/questions/56917088/show-mkpolyline-on-top-of-mapview-when-type-is-satelliteflyover