* feat: add more metrics for prometheus
* test: add test cases
* fix: check lint error
* remove hostname metrics. -> can't save string value.
* add more index
* add X-Etcd-Index
* fix lint
* test: add more test cases
* fix: Avoid the index to exceed 1000 by updating other keys that will causing a full reload
* add prev_index
* fix lint
* fix: fetch key first
* fix: test error
* fix update version only when waitdir error is timeout
* test
* fix: sleep more time
* fix: code style
* fix: code style
