GenericHeaderView.swift

struct HeaderView<LeftControls: View, RightControls: View>: View {
    init(
      viewModel: HeaderViewModel, 
      @ViewBuilder leftControls: @escaping () -> LeftControls, 
      @ViewBuilder rightControls: @escaping () -> RightControls) {
      
        // Assignments removed for brevety
    }
    
    private var viewModel: HeaderViewModel
    private let leftControls: () -> LeftControls
    private let rightControls: () -> RightControls
    
    var body: some View {
        ZStack {
            HStack {
                if let leftButtonTitle = viewModel.leftButtonTitle {
                    Button(leftButtonTitle) {
                        viewModel.leftButtonAction?()
                    }
                }
                
                leftControls()
                
                Spacer()
                rightControls()
            }
            
            Text(viewModel.title)
                .font(.title.bold())
        }
        .buttonStyle(.bordered)
    }
}