public DeleteTombstoneStats merge(DeleteTombstoneStats other) {
    //@formatter:off
    return new DeleteTombstoneStats(
        this.expiredCount + other.expiredCount,
        this.expiredSize + other.expiredSize,
        this.permanentCount + other.permanentCount,
        this.permanentSize + other.permanentSize,
        this.permanentSizeOneDay + other.permanentSizeOneDay,
        this.permanentSizeTwoDays + other.permanentSizeTwoDays,
        this.permanentSizeThreeDays + other.permanentSizeThreeDays,
        this.permanentSizeFiveDays + other.permanentSizeFiveDays,
        this.permanentSizeSevenDays + other.permanentSizeSevenDays,
        this.permanentSizeTenDays + other.permanentSizeTenDays,
        this.permanentSizeFourteenDays + other.permanentSizeFourteenDays
    );
    //@formatter:on
  }
Merge the given {@link DeleteTombstoneStats} to create a new {@link DeleteTombstoneStats}.
@param other The {@link DeleteTombstoneStats} to merge
@return A new {@link DeleteTombstoneStats} whose stats are the sum of this stats and the given stats.
ambry-api/src/main/java/com/github/ambry/store/DeleteTombstoneStats.java