prefetch example

public function testPreconnect()
    {
        $this->assertEquals('/foo.css', $this->extension->preconnect('/foo.css', ['as' => 'style', 'crossorigin' => true]));

        $link = (new Link('preconnect', '/foo.css'))->withAttribute('as', 'style')->withAttribute('crossorigin', true);
        $this->assertEquals([$link], array_values($this->request->attributes->get('_links')->getLinks()));
    }

    public function testPrefetch()
    {
        $this->assertEquals('/foo.css', $this->extension->prefetch('/foo.css', ['as' => 'style', 'crossorigin' => true]));

        $link = (new Link('prefetch', '/foo.css'))->withAttribute('as', 'style')->withAttribute('crossorigin', true);
        $this->assertEquals([$link], array_values($this->request->attributes->get('_links')->getLinks()));
    }

    public function testPrerender()
    {
        $this->assertEquals('/foo.css', $this->extension->prerender('/foo.css', ['as' => 'style', 'crossorigin' => true]));

        $link = (new Link('prerender', '/foo.css'))->withAttribute('as', 'style')->withAttribute('crossorigin', true);
        $this->assertEquals([$link], array_values($this->request->attributes->get('_links')->getLinks()));
    }

    public function prefetchExistences(WriteParameterBag $parameters): void
    {
        $primaryKeyBag = $this->primaryKeyBag = $parameters->getPrimaryKeyBag();

        if ($primaryKeyBag->isPrefetchingCompleted()) {
            return;
        }

        foreach ($primaryKeyBag->getPrimaryKeys() as $entity => $pks) {
            $this->prefetch($this->definitionInstanceRegistry->getByEntityName($entity), $pks, $parameters);
        }

        $primaryKeyBag->setPrefetchingCompleted(true);
    }

    /** * {@inheritdoc} */
    public function getExistence(EntityDefinition $definition, array $primaryKey, array $data, WriteCommandQueue $commandQueue): EntityExistence
    {
        $state = $this->getCurrentState($definition, $primaryKey, $commandQueue);

        

        $this->requestStack = $requestStack;
    }

    public function getFunctions(): array
    {
        return [
            new TwigFunction('link', $this->link(...)),
            new TwigFunction('preload', $this->preload(...)),
            new TwigFunction('dns_prefetch', $this->dnsPrefetch(...)),
            new TwigFunction('preconnect', $this->preconnect(...)),
            new TwigFunction('prefetch', $this->prefetch(...)),
            new TwigFunction('prerender', $this->prerender(...)),
        ];
    }

    /** * Adds a "Link" HTTP header. * * @param string $rel The relation type (e.g. "preload", "prefetch", "prerender" or "dns-prefetch") * @param array $attributes The attributes of this link (e.g. "['as' => true]", "['pr' => 0.5]") * * @return string The relation URI */