code: private Collection<MetricDatum> filterOSMetrics(Collection<MetricDatum> data) {
          Collection<MetricDatum> output = new ArrayList<MetricDatum>(data.size());
          for (MetricDatum datum: data) {
              if (!OS_METRIC_NAME.equals(datum.getMetricName()))
                  output.add(datum);
          }
          return output;
      }
docs: Return a collection of metrics almost the same as the input except with
  all OS metrics removed.