code: def _HandleFlowProcessingRequestLoop(self, handler):
      
      while not self.flow_handler_stop:
        with self.lock:
          todo = self._GetFlowRequestsReadyForProcessing()
          for request in todo:
            self.flow_handler_num_being_processed += 1
            del self.flow_processing_requests[(request.client_id,
                                               request.flow_id)]
  
        for request in todo:
          handler(request)
          with self.lock:
            self.flow_handler_num_being_processed -= 1
  
        time.sleep(0.2)
docs: Handler thread for the FlowProcessingRequest queue.