private const string host = "mongodb://localhost/";

        static void Main(string[] args)
        {
            MongoServer server = MongoServer.Create(host);

            MongoDatabase test = server.GetDatabase("testDB");

            List<int> list = Enumerable.Range(0, 100000).ToList();


            using (server.RequestStart(test))
            {
                MongoCollection coll = test.GetCollection("testCollection");

                server.IndexCache.Add(coll, "_id_");

                List<BsonValue> b = list.Select(l => BsonValue.Create(l)).ToList();
                var q = Query.In("_id", b);

                var found = coll.FindAs<BsonDocument>(q);
                found.SetFields(new[] {"_id"});

                DateTime start = DateTime.Now;
                var f = found.AsParallel().Select(fo => fo["_id"].AsInt32).ToList();

                Console.WriteLine(string.Format("Found {0} docs", f.Count));
                List<BsonDocument> documents = list.Except(f).Select(item => new BsonDocument { { "_id", item }, { "value", list[item] + list[item] } }).ToList();
                var updateDocs = list.Intersect(f);

                Console.WriteLine(string.Format("starting threads"));

                ThreadStart ts = () =>
                                     {
                                         documents = documents.AsParallel().Where(d => d != null).ToList();
                                         Console.WriteLine(string.Format("inserting {0} documents",documents.Count));
                                         coll.InsertBatch(documents, SafeMode.False);
                                     };
                Thread t = new Thread(ts);


                ThreadStart update = () => Parallel.ForEach(updateDocs, i =>
                                                                            {
                                                                                var query = new QueryDocument("_id", i);
                                                                                coll.Update(query,
                                                                                            Update.Set("value", i+i),
                                                                                            SafeMode.False);
                                                                            });
                Thread up = new Thread(update);

                up.Start();
                t.Start();

                t.Join();
                up.Join();

                DateTime end = DateTime.Now;
                Console.WriteLine(string.Format("Wrote {0} lines in {1}ms", list.Count, end.Subtract(start).TotalMilliseconds));
            }


        }