Emit a Length record on fetches from the backend.

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4979 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_fetch.c

@@ -516,6 +516,8 @@ FetchBody(struct sess *sp)
 		return (__LINE__);
 	}
 
+	WSL(sp->wrk, SLT_Length, sp->vbe->fd, "%u", sp->obj->len);
+
 	{
 	/* Sanity check fetch methods accounting */
 		unsigned uu;