Create empty IAsyncEnumerable

If you install the System.Linq.Async package, you should be able to use AsyncEnumable.Empty<string>(). Here’s a complete example:

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

class Program
{
    static async Task Main()
    {
        IAsyncEnumerable<string> empty = AsyncEnumerable.Empty<string>();
        var count = await empty.CountAsync();
        Console.WriteLine(count); // Prints 0
    }
}