// cache eviction.
  mutex_lock cluster_compile_lock(*cluster_mutex);
  auto cache_value = cache_->LookupOrCreate(signature);

  int64_t current_request_count = cache_value.request_count;
  VLOG(2) << "Compilation cache entry hit: "
          << static_cast<int>(cache_value.compile_state)
          << " signature: " << human_signature << " with request count "
          << current_request_count;

					// Next, get all matches.
					// This is a bit funky because the matches are oneof of ENUM and customer metric. We normalize
					// these to strings, so we may end up with a list like [REQUEST_COUNT, my-customer-metric].
					// TODO: we always flatten ALL_METRICS into each metric mode. For some stats providers (prometheus),
					// we are able to apply overrides to all metrics directly rather than duplicating the config.