Insanly huge agent cpu spike

還沒有人認領這個 Issue。

**Describe the bug**
Hi,
I am encountering huge CPU usage of the Micro ros agent running from docker as follows:
`docker run -it --rm -v /dev:/dev --privileged --net=host microros/micro-ros-agent:foxy udp4 -p 8888`

**To Reproduce**
Steps to reproduce the behaviour:
1. Clone repo 'micro_ros_arduino' Foxy Branch
2. Flash 8 ESPs with it (Client Key unique for each Esp)
3. Run Publisher example for 3 hours
4. CPU spike happens after around 3h
5. See CPU spike on htop

**Expected behaviour**
A normal usage of ~100% CPU usage max at all times.

**System information (please complete the following information):**
- OS: Ubuntu 20.04
- ROS 2 Foxy
- Hardware: 8x ESP32 micro-controllers running agent and client version 2.3.0

what can be the possible reason behind such a huge CPU usage?
Observation from my tests: it happens exponentially were it starts to increase to 200 then 500 then 1000%
And after the agent reaches past 200%, the Esp32 loses connection with the agent and fails to publish any messages.
Any help is much appreciated!

首先，在回報的 Ubuntu 20.04 與 ROS 2 Foxy 設定上使用八個 ESP32 用戶端執行提供的 Docker 指令，然後在 Publisher 範例執行期間監控 htop。重現 CPU 使用率延遲增長與連線遺失，識別造成該問題的 agent 行為，並驗證在所有用戶端持續發佈的同時 CPU 使用率保持穩定。

由索引模型根據 Issue 內容生成。