The stream format to use.
sfDeflate(0), sfZlib(1), sfGzip(2)
The stream format to use, by default Deflate.
All three stream formats use the Deflate algorithm specified in RFC 1951, which is the same algorithm used by Zip. The Zlib stream format adds a two-byte header and an Adler-32 checksum; the Gzip format adds a longer header and a CRC checksum, and is identical to the Gzip file format.
Caution: The terms zlib and deflate are sometimes used interchangeably (which is technically incorrect).