docs: public WxMpMessageRouterRule handler(WxMpMessageHandler handler, WxMpMessageHandler... otherHandlers) {
      this.handlers.add(handler);
      if (otherHandlers != null && otherHandlers.length > 0) {
        for (WxMpMessageHandler i : otherHandlers) {
          this.handlers.add(i);
        }
      }
      return this;
    }