Is your proposal related to a problem?

The Query/QueryRange does not return timing stats, along with sample stats. I can't say if this is intentional. Returning timing stats should be legit, at least if using Prometheus engine: I'm not really familiar with Thanos internals.

Describe the solution you'd like

Exposing timing stats should require few changes:

• add the related fields to the proto message for query stats
• map these fields in the func that extracts the query stats.

Please, see this tentative PR: #8638