* from, or send outgoing data via, fd. Very like _processany. If it
* returns zero then fd will no longer be readable or writeable
* (unless of course more data has arrived since). adns will _only_
* from, or send outgoing data via, fd. Very like _processany. If it
* returns zero then fd will no longer be readable or writeable
* (unless of course more data has arrived since). adns will _only_