Sorry, partly found the answer to the question in the last post of that topic When does a Task get scheduled to the Cooperative Thread Pool? - #4 by rayaantaneja
func someSyncWork() {}
func someAsyncWork() async {}
@MainActor
func someMainWork() async {}
...
func viewDidLoad() {
super.viewDidLoad()
Task {
someSyncWork() // Executed on main actor due to Task capturing actor context by default.
await someAsyncWork() // Executed on the global executor because someAsyncWork doesn't specify an actor context.
await someMainWork() // Executed on main actor because it specifies main actor.
}
}
So I made an example and it works fine
@MainActor
class MainThreadLock: ObservableObject {
@Published var text = "-"
func run() {
Task {
let k = await someParallelWork()
text.append("\(k)")
}
}
}
func someParallelWork() async -> Double {
let a = Array(0...10000000)
return a.reduce(0.0) { partialResult, z in
partialResult + Double(z) / 2
}
}
The main thread does not hang, because the someParallelWork() being executed in global thread pool.