/// <summary>
        /// Gets a collection of Todos.
        /// </summary>
        /// <param name="userId">The ID of the User to get Todos for (optional)</param>
        /// <returns>A collection of all available Todos</returns>
        public IEnumerable <Todo> GetTodos(int?userId = null)
        {
            Log.Debug($"Getting Todos");

            var request  = _client.CreateRequest("getTodos", new { userId });
            var response = _client.SendRequest <IEnumerable <Todo> >(request);

            Log.Debug($"Found {response.Count()} Todos");

            return(response);
        }