public function getPrefix()
  {
    $uuid = uniqid(static::CACHE_CHECK_PREFIX, true);
    $prefix = wp_cache_get($this->prefix, static::CACHE_GROUP_KEY, false, $uuid);

    if ($prefix !== $uuid) {
      return $prefix;
    }

    $this->setPrefix($this->prefix);
    return $this->getPrefix();
  }