C#MongoDB Driver $in

How about a simple "$in" query?

using MongoDB.Bson;
using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    public class MyClass
    {
        public ObjectId Id;
        public string Key;
    }

    public class Program
    {
        static void Main(string[] args)
        {
            IEnumerable<string> ids = new [] { "a", "b", "c" };

            var collection = new MongoClient().GetDatabase("test").GetCollection<MyClass>("test");

            foreach (var id in ids)
            {
                collection.InsertOne(new MyClass { Key = id });
            }

            // here comes the "$in" query
            var filter = Builders<MyClass>.Filter.In(myClass => myClass.Key, ids);

            // sync
            List<MyClass> values = collection.Find(filter).ToList();

            // async
            var queryTask = collection.FindAsync(filter);
            values = GetValues(queryTask).Result;

            Console.ReadLine();
        }

        private static async Task<List<MyClass>> GetValues(System.Threading.Tasks.Task<IAsyncCursor<MyClass>> queryTask)
        {
            var cursor = await queryTask;
            return await cursor.ToListAsync<MyClass>();
        }
    }
}