Daniel, So I'm looking at the async API, I guess right now although the return is passed by a callback, it's actually always synchronous, and called before returning from read2 or write2? So the callers need to be modified to be prepared for a true async callback. If they can't actually be async, they need to do their own signaling (they should be prepared for an inline callback or an async callback, for inline, they need to just do what their callback will need to let the main function know there was an inline response, otherwise, a non-async capable caller needs to wait on a condition variable or some other sleep and wakeup mechanism. I'll start to model that with NFS v4 ops. Frank