Downstreams assume process restarts when counters decrement. Currently,
the "active" label is expected to decrement but the "ok" and "error"
labels are intended to be handled as counters. This is unneccesary and
hard to deal with. This changes consolidate "blocking" and "in_flight"
tracking into a single guage, which allows fetch completion to be a pure
counter.
Kubernetes-commit: dc5934f58456d95b0264665871c0c48e16ee6469
request_total is fully accumulating, fetch_total is mostly accumulating
except for the active label.
Kubernetes-commit: a84e883e4b39f6a040d479b5be89b0750f4e7bf1
yoyinzyc
Mike Danese