General question on Serf

I have a question about how Serf works that I keep forgetting to send to
this list.

When you do an update with Serf, my understanding is that it does a REPORT
request that gives it back a list of files that it needs to update and then
it fires off a bunch of GET requests to retrieve those files. With Neon,
the changes are all included in the REPORT response.

My question is how this intersects with Deltas.

Suppose I have a large text file in my working copy and someone has made a
small minor change to the file. When using Neon, I know that the client
and server just exchange a relatively small delta that is applied to my
working copy. I imagine this delta is part of the REPORT response that the
client receives.

What happens with Serf? From what I know, I would assume that Serf has to
do a GET of the entire file. Is this true or does it somehow only request
a delta? And what might this mean for real world performance.

Kind of a side question. One of the benefits of the Serf design is that
theoretically enables the usage of caching proxies between the client and
server. This is another reason I assume that Serf must request the entire
file. I do not see how a caching proxy would provide much benefit if the
Serf requests were for somewhat arbitrary deltas between two revisions.

-- 
Thanks
Mark Phippard
http://markphip.blogspot.com/