Best practice in multi-thread app

[everwanna]

My app have a dispatchQ(DispatchQueue) for network requests and most other operations, and some other queues for heavy computing. I use PromiseKit like this,

    fetchData().then { objects in
        let tasks = objects.map { calculate($0 }
        return when(fulfilled: tasks)
    }.done {
    }.catch { error in
    }

PromiseKit is simple, I just use promise to replace those callbacks. Now I try to use AwaitKit, but soon I find out that await blocks current queue. dispatchQ can never be blocked because while waiting for network responses, the app might doing other small tasks in dispatchQ. I try to create awaitQ for waiting tasks like this,

    let awaitQ = DispatchQueue(label: "await")

    awaitQ.ak.async {
         let objects = try await(fetchData())
         let tasks = let tasks = objects.map { calculate($0 }
         try await(when(fulfilled: tasks))
    }

However, because dispatchQ have other tasks, awaitQ will still be blocked while waiting for one task. I will try to use DispatchQueue.global(qos: .userInitiated) to start more threads for waiting.

So, what is the best practice for app like this? Is it OK to start lots of threads for await?

[everwanna]

Thanks in advance!