code: public void enableRateLimitForward(String adminAPIKey, String endUserIP, String rateLimitAPIKey) {
      this.forwardAdminAPIKey = adminAPIKey;
      this.forwardEndUserIP = endUserIP;
      this.forwardRateLimitAPIKey = rateLimitAPIKey;
    }
docs: Allow to use IP rate limit when you have a proxy between end-user and Algolia.
  This option will set the X-Forwarded-For HTTP header with the client IP and the X-Forwarded-API-Key with the API Key having rate limits.
  
  @param adminAPIKey     the admin API Key you can find in your dashboard
  @param endUserIP       the end user IP (you can use both IPV4 or IPV6 syntax)
  @param rateLimitAPIKey the API key on which you have a rate limit