C#:在控制台应用程序的Main中调用异步方法会导致编译失败[closed]

我有一个非常简单的代码片段,用来测试如何调用Task<&燃气轮机;Main()中的方法

using System;
using System.Threading;
using System.Threading.Tasks;
class Program
{
    private static async Task<int> F1(int wait = 1)
    {
        await Task.Run(() => Thread.Sleep(wait));
        Console.WriteLine("finish {0}", wait);
        return 1;
    }

    public static async void Main(string[] args)
    {
        Console.WriteLine("Hello World!");
        var task = F1();
        int f1 = await task;
        Console.WriteLine(f1);
    }
}

它无法编译,因为:

(2) 编译器说:

error CS5001: Program does not contain a static 'Main' method suitable for an entry point

error CS4033: The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing its return type to 'Task'.

我可以在这里添加或删除“async”关键字。如何让它工作?谢谢。