
  -spec erlang:crc32(OldCrc, Data) -> non_neg_integer()
                        when OldCrc :: non_neg_integer(), Data :: iodata().

  Continues computing the crc32 checksum by combining the previous
  checksum, OldCrc, with the checksum of Data.

  The following code:

    X = erlang:crc32(Data1),
    Y = erlang:crc32(X,Data2).

  assigns the same value to Y as this:

    Y = erlang:crc32([Data1,Data2]).
