how to query istio metadata exchange data in envoy access log?

I know with the latest istio version, it start to integrate the metadata-exchange extension to envoy proxy, so that when communicate between each pod, envoy will potential use the "x-envoy-peer-metadata" header to exchange the pod metadata and save in metadata exchange extension cache.

So my questions is,

1. Is there a way that I can list the existing data in this metadata-exchange extension cache?
2. I know envoy proxy support DYNAMIC_METADATA in its access log format, is it related with the metadata-exchange extension?
3. Finally, how can I query the metadata in extension and log it in envoy access log. Such as, besides the DOWNSTREAM_REMOTE_ADDRESS, also i wish to output the downstream pod name.