 used to pass information to and from the <em>zlib</em> routines, and to maintain the
<tt>deflate()</tt> state.  <tt>in</tt> and <tt>out</tt> are the input and output buffers for
<tt>deflate()</tt>.
<pre><b>
    int ret, flush;
    unsigned have;
    z_stream strm;
    unsigned char in[CHUNK];
    unsigned char out[CHUNK];
</b></pre><!-- -->
The first thing we do is to initialize the <em>zlib</em> state for compression using
<tt>deflateInit()</tt>.  This must be done before the first use of <tt>deflate()</t