Generating an entity id manually in RavenDB

gistfile1.cs

        public async void Run()
        {
            var orderId = await GenerateId<Order>();
            var order = new Order(orderId, 10.99);

            session.Store(order);
            session.SaveChanges();
        }

        protected async Task<string> GenerateId<TEntity>()
        {
            var asyncSession = session as AsyncDocumentSession;

            var entity = Activator.CreateInstance(typeof(TEntity), true);

            // Generate an ID using the commands and conventions from the current session
            var databaseName = asyncSession.DatabaseName; 
            var databaseCommands = asyncSession.AsyncDatabaseCommands;
            return await asyncSession.DocumentStore.Conventions.GenerateDocumentKeyAsync(databaseName, databaseCommands, entity);
        }