public Optional<Value> getValueAt(String name, Map<String, String> dimensions) {
        return metricsList.stream()
                .filter(metric -> metric.name.equals(name))
                .filter(metric -> dimensions.entrySet().stream()
                        .allMatch(entry -> {
                            String dimensionName = entry.getKey();
                            Optional<String> requiredDimensionValue = Optional.ofNullable(entry.getValue());
                            return metric.getDimensionValue(dimensionName).equals(requiredDimensionValue);
                        }))
                .map(Metric::getValue)
                .findFirst();
    }
Get the metric value whose dimensions MUST MATCH the given dimensions map.
To require the metric to NOT have a dimension key, set it's value to null.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/hostinfo/Metrics.java