anchor.diff:  . Entries.
     Each entry contains:
   +
  -. Offset of the block referenced by this entry in the file (long)
  -. On>disk size of the referenced block (int)
  -. Key.
  +.. Offset of the block referenced by this entry in the file (long)
  +.. On-disk size of the referenced block (int)
  +.. Key.
     The length can be calculated from entryOffsets.
   
   
  
positive.code: 
  Scanned block section::
    The section is named so because it contains all data blocks that need to be read when an HFile is scanned sequentially.
    Also contains leaf block index and Bloom chunk blocks.
  Non-scanned block section::
    This section still contains unified-format v2 blocks but it does not have to be read when doing a sequential scan.
    This section contains "meta" blocks and intermediate-level index blocks.
  
negative.code: .. BLOOM_CHUNK – Bloom filter chunks
  .. META – meta blocks (not used for Bloom filters in version 2 anymore)
  .. INTERMEDIATE_INDEX – intermediate-level index blocks in a multi-level blockindex
  .. ROOT_INDEX – root-level index blocks in a multi-level block index
  .. FILE_INFO – the ''file info'' block, a small key-value map of metadata
  .. BLOOM_META – a Bloom filter metadata block in the load-on-open section
  .. TRAILER – a fixed-size file trailer.
    As opposed to the above, this is not an HFile v2 block but a fixed-size (for each HFile version) data structure
  .. INDEX_V1 – this block type is only used for legacy HFile v1 block
  . Compressed size of the block's data, not including the header (int).
  +
  