Which Realtime server events can give both input & output audio on the server side?

[pdeva03]

I am trying to retrieve audio files on the server side. Can you suggest which Realtime server events can give both input & output audio on the server side?

https://platform.openai.com/docs/api-reference/realtime-server-events

My purpose is to merge whole conversation audio on serve side and store as a single audio for whole conversation.