class UserNavigationBlock

final class UserNavigationBlock extends BlockBase implements ContainerFactoryPluginInterface {
    
    /**
     * Constructs the plugin instance.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
     *   The module handler.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, ModuleHandlerInterface $moduleHandler) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('module_handler'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function build() : array {
        return [
            'user' => [
                '#lazy_builder' => [
                    'navigation.user_lazy_builder:renderNavigationLinks',
                    [],
                ],
                '#create_placeholder' => TRUE,
                '#cache' => [
                    'keys' => [
                        'user_set_navigation_links',
                    ],
                    'contexts' => [
                        'user',
                    ],
                ],
                '#lazy_builder_preview' => [
                    '#markup' => '<a href="#" class="toolbar-tray-lazy-placeholder-link">&nbsp;</a>',
                ],
            ],
        ];
    }

}