参考资料：
https://www.baeldung.com/java-instrumentation
https://medium.com/@shehan.a.perera/using-a-java-agent-to-monitor-application-runtime-behavior-using-metrics-664eb95e971c
https://www.jrebel.com/blog/how-write-javaagent
https://github.com/toptal/jvm-monitoring-agent
https://ken-ljq.github.io/2018/JVM%E6%80%A7%E8%83%BD%E7%9B%91%E6%8E%A7Agent%E8%AE%BE%E8%AE%A1%E5%AE%9E%E7%8E%B0-%E4%B8%80/