public Map<DimensionId, String> getExtraDimensions() {
        purgeStaleMetrics();
        return this.extraDimensions;
    }
Returns the health metrics for the given services. The empty list is returned if no services are given.

@param services The services to retrieve health metrics for.
@return Health metrics for all matching services.
metrics-proxy/src/main/java/ai/vespa/metricsproxy/core/MetricsManager.java