Hi Pavel,
runUnixServer (serverSettings socket) $ \appData -> ... I want to store some data in priority queue in Monad.State and be able to access it inside the handleBS (now: handleBS :: ByteString -> ByteString).
Funnily enough, I've just been looking at an analogous problem (with runTCPClient and Persistent). It seems that in the recent move from conduit-network to conduit-extra, the run*Client and run*Server functions were specialized to the IO monad. I don't know what the motivation for this change was (simpler error messages perhaps?) but it does seem unhelpful. The workaround I deployed last night was to roll my own runTCPClient' which merges the code from the (deprecated) conduit-network package and the (current) streaming-commons, but this is hardly satisfactory. I'm sure I must be missing something. (I don't know if there's a better list to discuss conduit.) Toby.