How to set Mixed toggle in SwiftUI

MixedToggleStyle.swift

struct MixedToggleStyle: ToggleStyle {
    func makeBody(configuration: Configuration) -> some View {

        HStack {
            configuration.label
            Spacer()
            
            Button {
                configuration.isOn.toggle()
            } label: {
//                Image(
//                    systemName: configuration.isMixed
//                    ? "minus.circle.fill" : configuration.isOn
//                    ? "checkmark.circle.fill" : "circle")
                iconAndColor(for: configuration)
                .imageScale(.large)
            }
            .controlSize(.large)

        }

    }
    
    private func iconAndColor(for configuration: Configuration) -> some View {
        let icon: String
        let color: Color

        switch (configuration.isMixed, configuration.isOn) {
        case (true, _):
            icon = "minus.circle.fill"
            color = Color.secondary
        case (false, true):
            icon = "checkmark.circle.fill"
            color = Color.accentColor
        case (false, false):
            icon = "circle"
            color = Color.secondary
        }

        return Image(systemName: icon).foregroundStyle(color)
    }
}

#Preview {
    struct UserList: Identifiable {
        var id: UUID = .init()
        var name: String
        var isFollowing = false
    }
    
    struct PreviewWrapper: View {
        @State var lists = [
            UserList(name: "fatbobman (东坡肘子)", isFollowing: false),
            UserList(name: "Itsuki", isFollowing: false),
            UserList(name: "Kavsoft", isFollowing: false),
            UserList(name: "Sucodee", isFollowing: false),
            UserList(name: "Codelaby", isFollowing: false),
        ]

        var body: some View {
            Form {

                
                Section {
                    ForEach($lists) { $list in
                        Toggle(list.name, isOn: $list.isFollowing)
                            .id($list.id)
//                            .toggleStyle(SwitchToggleStyle(tint: .blue))
                    }
                 } header: {
                     Toggle("Follow favorite creators", sources: $lists, isOn: \.isFollowing)
                         .toggleStyle(MixedToggleStyle())
                 }
                
            }
        }
    }
    
    return VStack {
        PreviewWrapper()
        CreditsView()
    }
}