@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for (Metric m : metrics) {
            sb.append(m.getName()).append(":").append(m.getValue()).append("\n");
        }
        return sb.toString();
    }
Returns the size of the metrics covered. Note that this might also contain expired metrics.
metrics-proxy/src/main/java/ai/vespa/metricsproxy/metric/Metrics.java