返回Using块中间的Func<Task>

using System;

public class Program
{
    public static void Main()
    {
        DoSomethingAsync().Wait();
    }
    
    public static async Task DoSomethingAsync()
    {
        using (var resource = new SomeResource())
        {
            await Task.Delay(1000);
            Console.WriteLine("Async operation completed.");
        }
    }
}

public class SomeResource : IDisposable
{
    public SomeResource()
    {
        Console.WriteLine("Resource acquired.");
    }
    
    public void Dispose()
    {
        Console.WriteLine("Resource released.");
    }
}

Resource acquired.
Async operation completed.
Resource released.