How to turn on the Legacy metrics for envoy side car

[nguyenducthinhdl]

Dear team, I see that the commit 3114930. There are legacy metrics is described in https://docs.datadoghq.com/integrations/envoy/?tab=host (envoy.cluster.zone.upstream_rq_time.99percentile for example) and I'd like to turn on by datadog annotation.

My current annotation configuration is described bellow:

podAnnotations:
  ad.datadoghq.com/envoy-sidecar.check_names: '["openmetrics"]'
  ad.datadoghq.com/envoy-sidecar.init_configs: '[{}]'
  ad.datadoghq.com/envoy-sidecar.instances: |
    [
      {
        "openmetrics_endpoint": "http://%%host%%:20200/metrics",
        "metrics": [
          ".*"
        ]
      }
    ]

Could you give me some suggestion? Thanks.