UserCacheContext.php

<?php

namespace Drupal\Core\Cache\Context;

use Drupal\Core\Cache\CacheableMetadata;

/**
 * Defines the UserCacheContext service, for "per user" caching.
 *
 * Cache context ID: 'user'.
 */
class UserCacheContext extends UserCacheContextBase implements CacheContextInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getLabel() {
        return t('User');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getContext() {
        return $this->user
            ->id();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheableMetadata() {
        return new CacheableMetadata();
    }

}