Ios Task.cancel() 的 TaskPriority 的区别

我try 了代码所在的POST https://www.swiftbysundell.com/articles/building-an-async-swiftui-button/，但在 struct 中添加了优先级常量. 如果我使用的优先级是.utility，但如果我使用的是.userInitiated，则按钮正在做它应该做的事情(仅在Hibernate 时间结束时显示ProgressView，然后仅在操作完成之前显示ProgressView).为什么会这样呢？在触发showProgressView=TRUE语句之前，.cancel()函数不应该取消这两个操作吗？

当点击按钮".userInitiated"时，控制台输出为:

1. 任务已取消
2. 已创建任务

视频:https://imgur.com/a/SQJu1AM

struct ContentView: View{
    @State var count = 0
    @State var showProg = false
    func heavyTask() async throws ->Int{
        var k = count
        for _ in 0..<5_000_000{
            k += 1
        }
        return k
    }
    var body: some View{
        VStack{
            AsyncButton(action: {try? await count = heavyTask()},actionOptions: [.showProgressView], label: {
                Text(".utility")
            }, priority: .utility)
            AsyncButton(action: {try? await count = heavyTask()},actionOptions: [.showProgressView], label: {
                Text(".userInitiated")
            }, priority: .userInitiated)
            Text("result: \(count)")
        }
    }
}

struct AsyncButton<Label: View>: View {
    var action: () async -> Void
    var actionOptions = Set(ActionOption.allCases)
    @ViewBuilder var label: () -> Label
    let priority: TaskPriority

    @State private var isDisabled = false
    @State private var showProgressView = false

    var body: some View {
        Button(
            action: {
                if actionOptions.contains(.disableButton) {
                    isDisabled = true
                }
            
                Task {
                    var progressViewTask: Task<Void, Error>?

                    if actionOptions.contains(.showProgressView) {
                        progressViewTask = Task(priority: priority) {
                            try await Task.sleep(nanoseconds: 900_000_000)
                            showProgressView = true
                            print("已创建任务")
                        }
                        
                    }

                    await action()
                    progressViewTask?.cancel()
                    print("任务已取消")
                    isDisabled = false
                    showProgressView = false
                }
            },
            label: {
                ZStack {
                    label().opacity(showProgressView ? 0 : 1)

                    if showProgressView {
                        ProgressView()
                    }
                }
            }
        )
        .disabled(isDisabled)
    }
}


extension AsyncButton {
    enum ActionOption: CaseIterable {
        case disableButton
        case showProgressView
    }
}