public Zoo Get(string connectionString)
    {
        var database = new MongoDocumentsDatabase(connectionString);
        var task     = database.Zoo.Find(e => true).SingleAsync();

        task.Wait();
        return(task.Result);
    }
    public void Save(string connectionString)
    {
        var zoo = new Zoo
        {
            Animals = new List <Animal>
            {
                new Tiger
                {
                    Height = 1,
                    Name   = "Tiger1"
                },
                new Zebra
                {
                    Name          = "Zebra1",
                    StripesAmount = 100
                }
            }
        };
        var database = new MongoDocumentsDatabase(connectionString);

        database.Zoo.InsertOneAsync(zoo).Wait();
    }