Constructor.
\Drupal\rest\LinkManager\TypeLinkManagerInterface $type_link_manager: Manager for handling bundle URIs.
\Drupal\rest\LinkManager\RelationLinkManagerInterface $relation_link_manager: Manager for handling bundle URIs.
public function __construct(TypeLinkManagerInterface $type_link_manager, RelationLinkManagerInterface $relation_link_manager) {
$this->typeLinkManager = $type_link_manager;
$this->relationLinkManager = $relation_link_manager;
}