Marks a cache item as invalid.
Invalid items may be returned in later calls to get(), if the $allow_invalid argument is TRUE.
string $cid: The cache ID to invalidate.
Drupal\Core\Cache\CacheBackendInterface::delete()
Drupal\Core\Cache\CacheBackendInterface::invalidateMultiple()
Drupal\Core\Cache\CacheBackendInterface::invalidateTags()
Drupal\Core\Cache\CacheBackendInterface::invalidateAll()
public function invalidate($cid);