private void debugDump(StringBuilder result) {
      result.append("\nArena: ");
      if (data == null) {
        result.append(" not allocated");
        return;
      }
      // Try to get as consistent view as we can; make copy of the headers.
      byte[] headers = new byte[this.headers.length];
      System.arraycopy(this.headers, 0, headers, 0, headers.length);
      int allocSize = minAllocation;
      for (int i = 0; i < freeLists.length; ++i, allocSize <<= 1) {
        result.append("\n  free list for size " + allocSize + ": ");
        FreeList freeList = freeLists[i];
        freeList.lock.lock();
        try {
          int nextHeaderIx = freeList.listHead;
          while (nextHeaderIx >= 0) {
            result.append(nextHeaderIx + ", ");
            nextHeaderIx = getNextFreeListItem(offsetFromHeaderIndex(nextHeaderIx));
          }
        } finally {
          freeList.lock.unlock();
        }
      }
      for (int i = 0; i < headers.length; ++i) {
        byte header = headers[i];
        if (header == 0) continue;
        int freeListIx = freeListFromHeader(header), offset = offsetFromHeaderIndex(i);
        boolean isFree = buffers[i] == null;
        result.append("\n  block " + i + " at " + offset + ": size "
            + (1 << (freeListIx + minAllocLog2)) + ", " + (isFree ? "free" : "allocated"));
      }
    }
Unsets the headers (meaning this does not refer to a buffer).
llap-server/src/java/org/apache/hadoop/hive/llap/cache/BuddyAllocator.java