private void setHeaderNoBufAlloc(int headerIndex, int freeListIx, CasLog.Src src) {
      headers[headerIndex] = makeHeader(freeListIx, true);
      CasLog.logSetNb(src, arenaIx, headerIndex, allocSizeFromFreeList(freeListIx));
    }
Sets the header at an index to refer to some space in use, without an allocation.
llap-server/src/java/org/apache/hadoop/hive/llap/cache/BuddyAllocator.java