docs: public void sendAckData(List<Object> objs) {
          if (!isAckRequested() || !sended.compareAndSet(false, true)) {
              return;
          }
          Packet ackPacket = new Packet(PacketType.MESSAGE);
          ackPacket.setSubType(PacketType.ACK);
          ackPacket.setAckId(originalPacket.getAckId());
          ackPacket.setData(objs);
          client.send(ackPacket);
      }