private static MetricSet getDocprocMetrics() {
        return new MetricSet.Builder("default-docproc")
                .metric(ContainerMetrics.DOCPROC_DOCUMENTS.sum())
                .build();
    }
Metrics for the 'default' consumer, which is used by default for the generic metrics api and
other user facing apis, e.g. 'prometheus/'.

@author gjoranv
@author yngve
metrics/src/main/java/ai/vespa/metrics/set/Vespa9DefaultMetricSet.java