SwiftUI tap on a MapAnnotation

Hey Guys,

i want to create a MapView in SwiftUI that gets a list of markers and displays them. But I also want the user to be able to click/tap on them. If they get tapped they should flip a bool to mark them as done.

I've created a mockup array for my markers:

Code Block 
struct Marker: Identifiable {
    let id = UUID()
    var coordinate : CLLocationCoordinate2D
    var done : Bool
}
let markers = [
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.882975, longitude: 10.558585), done: true),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.883329, longitude: 10.559225), done: true),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.883296, longitude: 10.558216), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.882614, longitude: 10.559574), done: true),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.882425, longitude: 10.559263), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.882607, longitude: 10.557679), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.883246, longitude: 10.557652), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.883753, longitude: 10.557711), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.884018, longitude: 10.558710), done: false),
    Marker(coordinate: CLLocationCoordinate2D(latitude: 51.881783, longitude: 10.559713), done: false),
]

The problem is that nothing is happening when I tap on the markers. I've tried to print, toggle a bool, navigate etc. in .onTapGesture { }

Here is the code for my Map:

Code Block 
Map(coordinateRegion: $region, annotationItems: markers) { marker in
       MapAnnotation(coordinate: marker.coordinate) {
           Circle()
               .onTapGesture {
                   // do something
               }
       }
}

$region is this:

Code Block 
@State private var region = MKCoordinateRegion(
        center: CLLocationCoordinate2D(latitude: 51.882879, longitude: 10.558918),
        span: MKCoordinateSpan(
            latitudeDelta: 0.01,
            longitudeDelta: 0.01
        )
    )

Hope someone can help!