code: public void getToken(GetTokenHandler handler) {
          HMSAgentLog.i("getToken:handler=" + StrUtils.objDesc(handler));
          this.handler = handler;
          retryTimes = MAX_RETRY_TIMES;
          connect();
      }
docs: 获取pushtoken接口
  pushtoken通过广播下发，要监听的广播，请参见HMS-SDK开发准备中PushReceiver的注册
  @param handler pushtoken接口调用回调