short getResetKeyLifeVersion() throws StoreException {
    if (resetKeyInfo == null) {
      return UNINITIALIZED_RESET_KEY_VERSION;
    }
    if (resetKeyInfo.getResetKeyLifeVersion() != UNINITIALIZED_RESET_KEY_VERSION) {
      return resetKeyInfo.getResetKeyLifeVersion();
    }
    NavigableSet<IndexValue> indexValues = find(resetKeyInfo.getResetKey());
    // reset key should be present in current index segment, hence indexValues is guaranteed to be non-empty
    return indexValues.first().getLifeVersion();
  }
@return life version of reset key.
ambry-store/src/main/java/com/github/ambry/store/IndexSegment.java