anchor.diff:  
   %%--------------------------------------------------------------------
   %% @doc
  -%% 
  +%%
   %% @end
   %%--------------------------------------------------------------------
   -spec write(mfile(), pos_integer(), binary(), non_neg_integer(), binary()) ->
  
positive.code:     FunAcc1 = Fun(O, Acc, FunAcc),
      VSize =DataSize - 1,
      <<_:VSize/binary, R1/binary>> = R,
    serialize_binary(DataSize, R1, Fun, FunAcc1, O+mmath_bin:length(Acc)+1, <<>>);
  serialize_binary(DataSize, R, Fun, FunAcc, O, Acc) ->
      <<V:DataSize/binary, R1/binary>> = R,
      serialize_binary(DataSize, R1, Fun, FunAcc, O, <<Acc/binary, V/binary>>).
  
negative.code:                          Offset :: non_neg_integer(),
                           Data :: binary(), AccIn :: any()) -> AccOut :: any()).
  
  -type open_error_reason() :: file:posix() | badarg | system_limit |
                               offset_missmatch | size_missmatch.
  
  -type read_error_reason() :: file:posix() | badarg | terminated | not_found.
  