As the official doc points out, if use UDP socket every time a API like send or recv called, a crossdomain.xml request is needed. If this is true,it give udp a big performence hit. But as I tried out it seems only one xml request happens. Is the document about sandbox out-dated? Or I just missed something? Is UDP usable or not for webplayer?
It is usable and the crossdomain request is only done once per server you want to communicate with. It’s skipped alltogether if the webplayer and socket server are on the same domain.