   0: actor start
   0/0: actor about to sleep
   0: interrupter start
   2/0: actor wakes with None
   2/1: actor about to sleep
   3/0: scheduling interrupt
   3/1: actor interrupted with message
   3/2: actor about to sleep
   4/2: actor wakes with None
   4/3: actor about to sleep
   5/3: actor wakes with None
   5: actor end
   6/1: scheduling interrupt
   6: interrupter end
