CSharpAsyncRecursion.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace CSharpAsyncRecursion
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Counted to {0}.", CountRecursivelyAsync(10000).Result);
        }

        static async Task<int> CountRecursivelyAsync(int count)
        {
            await Task.Yield();
            if (count <= 0)
                return count;
            var result = 1 + await CountRecursivelyAsync(count - 1);
            await Task.Yield();
            return result;
        }
    }
}