我尝试使用init来调用ViewModel类中的fetchProducts函数。但是当我添加init时，我得到了以下2个错误：
Variable 'self.countries' used before being initialized
以及
Return from initializer without initializing all stored properties
变量countries是绑定的，所以在这个视图中不需要初始化值。我用错init了吗？

struct ContentView: View {
    
    @Namespace var namespace;
    @Binding var countries: [Country];
    @Binding var favLists: [Int];
    @State var searchText: String = "";

    @AppStorage("numTimeUsed") var numTimeUsed = 0;
    @Environment(\.requestReview) var requestReview
    
    @StateObject var viewModel = ViewModel();
    
    init() {
        viewModel.fetchProducts()
    }

    var body: some View {

    }

}