micrometer
https://micrometer.io/
https://github.com/micrometer-metrics/micrometer

https://micrometer.io/docs
https://micrometer.io/docs/concepts
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready-metrics
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready-endpoints-exposing-endpoints
https://micrometer.io/docs/ref/jvm
https://micrometer.io/docs/ref/cache

api
https://static.javadoc.io/io.micrometer/micrometer-core/1.1.4/io/micrometer/core/instrument/Timer.html

exposing endpoint
management:
  server:
    port: 9090
    security:
      enabled: false
  endpoints:
    web:
      base-path: /application
      exposure:
        include: info,health,prometheus

2021
https://spring.io/blog/2021/02/09/metrics-and-tracing-better-together
2019
https://dzone.com/articles/spring-boot-where-do-the-default-metrics-come-from
https://www.infoq.com/presentations/metrics-apache-geode-micrometer
https://www.baeldung.com/micrometer
2018
https://dzone.com/articles/using-micrometer-with-spring-boot-2
https://spring.io/blog/2018/03/16/micrometer-spring-boot-2-s-new-application-metrics-collector

http://www.ryantenney.com/metrics-spring/
    https://github.com/ryantenney/metrics-spring

annotations
https://github.com/micrometer-metrics/micrometer/blob/master/micrometer-core/src/main/java/io/micrometer/core/annotation/Timed.java