API:       "SYSTEM",
			RequestID: fmt.Sprintf("%X", time.Now().UTC().UnixNano()),
		}
	}
	req.RLock()
	defer req.RUnlock()

	API := "SYSTEM"
	switch {
	case req.API != "":
		API = req.API
	case subsystem != "":
		API += "." + subsystem
	}

	// Copy tags. We hold read lock already.
	tags := make(map[string]interface{}, len(req.tags))
	for _, entry := range req.tags {