A semantic that came up in discussions about Riak: we could return the current value if we're failing a WT_CURSOR::insert call with key-exist.
One risk: we'd be discarding the application-set value of the WT_CURSOR::insert call, replacing it with something else.
This means loops like:
would require one less engine call.
Michael, I didn't want this one to get lost, kill it if you don't like it.