This section describes how you can make a stream that gets input from an
arbitrary data source or writes output to an arbitrary data sink
programmed by you. We call these custom streams. The functions
and types described here are all GNU extensions.
Streams and Cookies: The cookie records where to fetch or
store data that is read or written.
Hook Functions: How you should define the four hook
functions that a custom stream needs.
Published under the terms of the GNU General Public License
