[xml] xmlDocDumpMemory to my own buffer?

[Rick Jones <rick jones2 hp com>]

Is there a call akin to  xmlDocDumpMemory where I can supply the buffer?

In netperf4, I presently use xmlDocDumpMemory and then send that buffer, 
prefixed with a four byte length field out a socket via sendmsg().  as 
part of porting to windows I am porting to glib and its IO channels, 
which do not appear to have a "gathering" write a la sendmsg() and I 
would like to avoid copying the dumped XML.

So, I'd like to be able to provide the buffer into which the doc is 
dumped, so I can have libxml put the stuff after where the header would 
go and then I just ahve the one buffer.

I do _not_ want to make two separate send calls - when the data is 
logically associated as it is here it is an application bug to do so 
(IMO) and only invites trouble with performance.

rick jones