Why disk_log_1 need MD5 check?

Questions / Help
,
1

there is a define at disk_log.hrl

-define(MIN_MD5_TERM, 65528).% (?MAX_CHUNK_SIZE - ?HEADERSZ)

and using at disk_log_1.erl

logl([X | T], Bs, Size) ->
    Sz = byte_size(X),
    BSz = <<Sz:?SIZESZ/unit:8>>,
    NBs = case Sz < ?MIN_MD5_TERM of
              true ->
                  [Bs, BSz, ?BIGMAGICHEAD | X];
              false ->
                  MD5 = erlang:md5(BSz),
                  [Bs, BSz, ?BIGMAGICHEAD, MD5 | X]
              end,
    logl(T, NBs, Size + ?HEADERSZ + Sz);

I am curious about why an MD5 check is necessary.