unix socket: Get flow information by flow_id
When a flow is long duration and is not yet dead, we can know it exists (via application layer logging) but we can't know anything about the volume of data exchanged. This is not helping to characterize the nature of the flow. For example, we can not differentiate a scp session and a ssh session (same example work on TLS tunnel).
A way to get information is to be able to query the unix socket to get the volumetry information from the flow.