private void setHeaderAlloc(int headerIx, int freeListIx, LlapAllocatorBuffer alloc,
        CasLog.Src src) {
      assert alloc != null;
      headers[headerIx] = makeHeader(freeListIx, true);
      buffers[headerIx] = alloc;
      CasLog.logSet(src, arenaIx, headerIx, System.identityHashCode(alloc));
    }
Sets the header at an index to refer to an allocated buffer.
llap-server/src/java/org/apache/hadoop/hive/llap/cache/BuddyAllocator.java