See what you mean.
What we want is to be able to pass in (linked) Actors instead of event
handlers here:

 read_source.setEventHandler(^{ read })
 read_source.setCancelHandler(^{ close })

This would require a change in HawtDispatch (if we want to do it cleanly)

If you link Session to Server then I guess you could do something like
this. Change the catchio fun to this:

  private def catchio(func: =>Unit):Unit = {
     try {
       func
     } catch {
       case e:IOException => close
       case e => server ! Exit(self, e)
     }
   }

That should restart the Session actor instance. This requires this
code to create the Session:

    val session = actorOf(new Session(self, socket))
    self.startLink(session)
    sessions += session

Let me know if it works.