docs: @Override
      public DataPoint get(long timestampMs) {
          long key = toTimeSeriesPoint(timestampMs);
          if (counter.containsKey(key)) {
              long value = counter.get(key);
              return new DataPoint(Type.SUM, key, value, RESOLUTION_MS);
          } else {
              return new DataPoint(Type.NONE, key, 0, RESOLUTION_MS);
          }
      }