KMultiPart implements "server push" for KHTML/Konqueror:
it handles the multipart/mixed and multipart/x-mixed-replace
mimetype, embedding the appropriate component (part).

Documentation used to be at http://www.netscape.com/assist/net_sites/pushpull.html
 but that site is gone nowadays.

Found more docs at:
 http://www.kiv.zcu.cz/~ledvina/vyuka/books/HTMLnya/ch38.htm
 https://docstore.mik.ua/orelly/web/html/ch14_03.html

Typical real-world uses: webchats, webcams...

Testcases:
  http://217.173.193.218/axis-cgi/mjpg/video.cgi?resolution=704x576,
  http://wtb.cc:5050
  http://palantir.santinoli.com:14334/
  http://moosworld.dyndns.org:4033/nphMotionJpeg?Resolution=320x240&Quality=Standard&NUMBER=1&time=1239198646918
  http://www.airport-nuernberg.de/_/tools/webcam.html?_FRAME=64&refresh=2&datei=webcam-0-0.jpg&bildpaket=1&oldcam=oldcam&pid=12541   (bug 123614)
  http://www.geodata.co.uk/sbc/    (bug 120220)
  http://www.fastpath.it/products/palantir/demo.html  (bug 115286)
  http://cpansearch.perl.org/src/LDS/CGI.pm-3.43/examples/index.html [does not work anymore]
  r257583 mentionned expedia.ca for the gzip encoding, need to add pmax for details

TODO:
* Use the new streaming API of KParts to pipe data into the part,
the current code does that for KHTML only.
* Change KHTML so that it embeds KMultiPart for images which send multipart/x-mixed-replace
data.
