Describe the feature you'd like to request

We would like a way to pass arbitrary metadata to the remote cache endpoints, so we can collect more specific metrics around the cache hits / misses.

We are currently able to use the events endpoint to log the cache hit / miss, hash specified, and local v. remote cache hit from the source value - but we would like to distinguish further.

For example, we would like a way to signify where the request came from: i.e. a local request, a development pipeline, a production pipeline, or an ephemeral env pipeline. For the pipeline cases, we would also like to record information about the specific pipeline / action (i.e. a pipeline ID and specific build/job ID).

Describe the solution you'd like

One option may be to support arbitrary environment variables with a particular prefix, i.e. anything named TURBOREPO_REMOTE_CACHE_<KEY> added to the payload.

Ideally the solution would not be opinionated about the specific keys / data added to the events payload, and be easy to change between build envs.

Describe alternatives you've considered

Open to discussion / suggestion.