public void addAllSublists(List<? extends List<T>> items) {
    for (List<T> list : items) {
      addSublist(list);
    }
  }
A collection class that contains multiple sub-lists, which allows us to not copy lists. This
class does not support modification. The derived classes that add modifications are not
thread-safe. NOTE: Doesn't implement list as it is not necessary for current usage, feel free to
add.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/ConcatenatedLists.java