docs: public void shutdown() {
      if (shutdown) {
        return;
      }
      cache.clear();
      stats.shutdown();
      dispatcher.shutdown();
      if (closeableCache != null) {
        try {
          closeableCache.close();
        } catch (IOException ignored) {
        }
      }
      for (DeferredRequestCreator deferredRequestCreator : targetToDeferredRequestCreator.values()) {
        deferredRequestCreator.cancel();
      }
      targetToDeferredRequestCreator.clear();
      shutdown = true;
    }