code: public void mergeMeters(MetricInfo metricInfo, String meta, Map<Integer, MetricSnapshot> data) {
          Map<Integer, MetricSnapshot> existing = metricInfo.get_metrics().get(meta);
          if (existing == null) {
              metricInfo.put_to_metrics(meta, data);
          } else {
              for (Map.Entry<Integer, MetricSnapshot> dataEntry : data.entrySet()) {
                  Integer win = dataEntry.getKey();
                  MetricSnapshot snapshot = dataEntry.getValue();
                  MetricSnapshot old = existing.get(win);
                  if (old == null) {
                      existing.put(win, snapshot);
                  } else {
                      if (snapshot.get_ts() >= old.get_ts()) {
                          old.set_ts(snapshot.get_ts());
                          old.set_mean(old.get_mean() + snapshot.get_mean());
                          old.set_m1(old.get_m1() + snapshot.get_m1());
                          old.set_m5(old.get_m5() + snapshot.get_m5());
                          old.set_m15(old.get_m15() + snapshot.get_m15());
                      }
                  }
              }
          }
      }
docs: meters are not sampled.