protected boolean addValueSample(int statOffset, long statDeltaBits) {
      if (values != null && values[statOffset] != null) {
        values[statOffset].prepareNextBits(statDeltaBits);
        return true;
      } else {
        return false;
      }
    }
Returns true if sample was added.
geode-core/src/main/java/org/apache/geode/internal/statistics/StatArchiveReader.java