AsyncTest.swift

import SwiftUI

@main
struct AsyncTestApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(State())
        }
    }
}

class State: ObservableObject {
    @Published var counter: Int = 0

    func increase() async {
        _ = Task {
            counter += 1
        }
    }
}

struct ContentView: View {
    @EnvironmentObject var state: State

    var body: some View {
        VStack {
            Text(String(state.counter))
            Button("Increase") {
                Task {
                    await state.increase()
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .environmentObject(State())
    }
}