code: def _wait_trigger(self):
          
          if _debug: IOQController._debug("_wait_trigger")
  
          # make sure we are waiting
          if (self.state != CTRL_WAITING):
              raise RuntimeError("not waiting")
  
          # change our state
          self.state = CTRL_IDLE
          _statelog.debug("%s %s %s" % (_strftime(), self.name, "idle"))
  
          # look for more to do
          IOQController._trigger(self)
docs: Called to launch the next request in the queue.