如何:将异步方法与LINQ自定义扩展方法一起使用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

public static class AsyncEnumerableExtensions
{
    public static async IAsyncEnumerable<T> WhereAsync<T>(this IAsyncEnumerable<T> source, Func<T, Task<bool>> predicate)
    {
        await foreach (var item in source)
        {
            if (await predicate(item))
            {
                yield return item;
            }
        }
    }
}

public class Program
{
    public static async Task Main(string[] args)
    {
        var numbers = Enumerable.Range(1, 10).AsAsyncEnumerable();

        var filteredNumbers = numbers.WhereAsync(async x => await Task.Run(() => x % 2 == 0));

        await foreach (var number in filteredNumbers)
        {
            Console.WriteLine(number);
        }
    }
}