public static OptionalLong getMaxSequenceIdInList(Collection<HStoreFile> sfs) {
    return sfs.stream().mapToLong(HStoreFile::getMaxSequenceId).max();
  }
Return the highest sequence ID found across all storefiles in the given list.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreUtils.java