I was searching through the API, though I couldn't seem to find
anything relevant. There used to be a `cb = arnold.AtDisplayCallBack(_callback)` attribute which I used to pass in
`x,y,width,buffer,data` and then use it with `arnold.AiNodeSetPtr(driver, "callback", cb)` for the purposes of
displaying rendered tiles/IPR.
Do you have any idea what this
might have been changed to? Or is there a better way of writing display
drivers with Arnold 5? Thanks.