Future::__call PHP Method

    public function __call($method, $args)
    {
        if ($args === NULL) {
            $args = array();
        }
        return $this->then(function ($result) use($method, $args) {
            return all($args)->then(function ($args) use($result, $method) {
                return call_user_func_array(array($result, $method), $args);
            });
        });
    }