edlp_d8/core/modules/workspaces/src/WorkspacesServiceProvider.php

<?php

namespace Drupal\workspaces;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\DependencyInjection\ServiceProviderBase;

/**
 * Defines a service provider for the Workspaces module.
 */
class WorkspacesServiceProvider extends ServiceProviderBase {

  /**
   * {@inheritdoc}
   */
  public function alter(ContainerBuilder $container) {
    // Add the 'workspace' cache context as required.
    $renderer_config = $container->getParameter('renderer.config');
    $renderer_config['required_cache_contexts'][] = 'workspace';
    $container->setParameter('renderer.config', $renderer_config);
  }

}