malkusch\lock\util\DoubleCheckedLocking::then PHP Метод

    public function then(callable $code)
    {
        if (!call_user_func($this->check)) {
            return;
        }
        $this->mutex->synchronized(function () use($code) {
            if (call_user_func($this->check)) {
                call_user_func($code);
            }
        });
    }