public function executeMediaReactions($reaction_type, MediaInterface $media) {
    $provider = new MediaContextProvider($media);
    $provided = $provider->getRuntimeContexts([]);
    $this->contextManager->evaluateContexts($provided);

    // Fire off index reactions.
    foreach ($this->contextManager->getActiveReactions($reaction_type) as $reaction) {
      $reaction->execute($media);
    }
  }