zlib compression level to use (0-9), where 1 is the fastest
at the expense of larger files, and 9 produces the best
compression at the expense of speed. 0 indicates that no
compression should be performed. -1 is the default (currently
optimizing for speed).
zlib compression level to use (0-9), where 1 is the fastest at the expense of larger files, and 9 produces the best compression at the expense of speed. 0 indicates that no compression should be performed. -1 is the default (currently optimizing for speed).