class ExtensionMimeTypeGuesser

class ExtensionMimeTypeGuesser implements \Symfony\Component\Mime\MimeTypeGuesserInterface {
    use \Drupal\Core\DependencyInjection\DependencySerializationTrait;
    
    /**
     * The id of the original proxied service.
     *
     * @var string
     */
    protected $drupalProxyOriginalServiceId;
    
    /**
     * The real proxied service, after it was lazy loaded.
     *
     * @var \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser
     */
    protected $service;
    
    /**
     * The service container.
     *
     * @var \Symfony\Component\DependencyInjection\ContainerInterface
     */
    protected $container;
    
    /**
     * Constructs a ProxyClass Drupal proxy object.
     *
     * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
     *   The container.
     * @param string $drupal_proxy_original_service_id
     *   The service ID of the original service.
     */
    public function __construct(\Symfony\Component\DependencyInjection\ContainerInterface $container, $drupal_proxy_original_service_id) {
        $this->container = $container;
        $this->drupalProxyOriginalServiceId = $drupal_proxy_original_service_id;
    }
    
    /**
     * Lazy loads the real service from the container.
     *
     * @return object
     *   Returns the constructed real service.
     */
    protected function lazyLoadItself() {
        if (!isset($this->service)) {
            $this->service = $this->container
                ->get($this->drupalProxyOriginalServiceId);
        }
        return $this->service;
    }
    
    /**
     * {@inheritdoc}
     */
    public function guessMimeType($path) : ?string {
        return $this->lazyLoadItself()
            ->guessMimeType($path);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setMapping(?array $mapping = NULL) {
        return $this->lazyLoadItself()
            ->setMapping($mapping);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isGuesserSupported() : bool {
        return $this->lazyLoadItself()
            ->isGuesserSupported();
    }

}