No guide for using benchmark tool behind proxy

[joshuayao]

It would be great to add the guide for proxy environment.

E.g. If we enable collect_service_metric and provide service-list, benchmark tool will use container IPs of the pods in service-list to fetch metrics, but container IPs would not be able to access behind proxy. We need to add them into no_proxy.

[yinghu5]

[Remind] Joshuayao will take care the issue

[joshuayao]

[Remind] Joshuayao will take care the issue

Hi Merry, thanks for your reminder. I added the label 'Backlog'.