static function start(?callable $callback = null) {
        parent::start(function () use ($callback) {
            if (is_callable($callback))
                $callback();
            if (ENABLE_SESSION)
                HttpCache::init();
        });
    }
static function start(?callable $callback = null) {
        parent::start(function () use ($callback) {
            if (is_callable($callback))
                $callback();
            if (ENABLE_SESSION)
                HttpCache::init();
        });
    }
{@inheritdoc}