An output stream.
A stream buffer.
Bounding indexes for a subsequence of buffer .
The generic function
is called by stream-flush-buffer to write the region of the buffer bounded by
to the stream's underlying data sink.
stream should be an instance of a subclass of buffered-stream.
This method must be implemented for subclasses of buffered-stream that handle output.
LispWorks User Guide and Reference Manual - 21 Dec 2011