Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* make sync metrics concurrency

* add changelog

* add changelog

* polish codes

* change default value

* remove unnecessary codes
Co-authored-by: NEvan <evanljp@outlook.com>
Co-authored-by: NZhenxu Ke <kezhenxu94@apache.org>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Append the root slash(/) to getIndex and getTemplate requests
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Document this bug
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Fix ALS K8SServiceRegistry didn't remove the correct entry

* Add changes
Co-authored-by: NZhenxu Ke <kezhenxu94@apache.org>

Add  arg `namespace` to func `retagByK8sMeta`, rebuild the relationship between pod and service by labels (#6650)

* Add `namespace` to func `retagByK8sMeta`, rebuild the relationship between pod and service by labels

* add param check

Add function `retagByK8sMeta` and opt type `K8sRetagType.Pod2Service` in MAL for k8s to relate pods and services. (#6608)

Support metrics grouped by scope labelValue in MAL, no need global same labelValue as before. (#6495)

Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

Add telemetry data about metrics in, metrics scraping and trace in metrics to zipkin receiver. (#6516)

* Add `sum` function in meter system

* Fix minor potential bug and reformat some codes

* Fix a bug

* Use Set to hold the {aggregate,scope} labels as same labels maybe added by multiple aggregation functions

* Separate downsampling function and revert unnecessary codes