class PrometheusMetricsSystem implements ObservableMetricsSystem {

  @Override
  public Stream<Observation> streamObservations(final MetricCategory category) {
    return collectors.getOrDefault(category, Collections.emptySet()).stream()
        .flatMap(collector -> collector.collect().stream())
        .flatMap(familySamples -> convertSamplesToObservations(category, familySamples));
  }

    PrometheusMetricsSystem(
      final Set<MetricCategory> enabledCategories, final boolean timersEnabled);

}