When I tried this, Xcode encountered an error that Instance method 'onChange(of:perform:)' requires that 'MKCoordinateRegion' conform to 'Equatable' I ended up adding a didSet: final class MapConfig: ObservableObject {   var region: MKCoordinateRegion = MKCoordinateRegion(...)   {     didSet {       print("changed to \(region)")     }   } } struct ChooseLocationView: View {   @ObservedObject var config = MapConfig()        var body: some View {     ZStack {       Map(coordinateRegion: $config.region,       interactionModes: .all,       showsUserLocation: true,       userTrackingMode: nil)     } 	} }