prefetchDNS() in DNSCFNet.cpp is not implemented.
Created attachment 34981 [details]
Comment on attachment 34981 [details]
> 54 host.releaseRef(); // The host will be released from callback.
I'd change this to "The host will be released in clientCallback".
Committed revision 47391.
Made one post-review change: with a null callback info, CFHostStartInfoResolution() works synchronously, even if the client has been set.