##### SUMMARY
Since `add_host` and `group_by` actions only modify the runtime inventory, hosts/groups/vars added by them don't survive a `meta: refresh_inventory` call (since that call completely clears the runtime inventory). 

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
InventoryManager

##### ADDITIONAL INFORMATION
After some internal discussion, the general consensus seemed to be that this behavior is an undesirable default. The `add_host` and `group_by` actions should manage a more persistent state independent of the runtime inventory, then apply their changes to the running inventory. When a `meta: refresh_inventory` occurs, the normal dynamic inventory clear/refresh should happen, then reapply the add_host/group_by state. This should probably be the default behavior, but a config switch or a different `meta` action (or an arg to it) to emulate the current behavior could also be created if necessary.

}
                    worker_prc = WorkerProcess(self._final_q, task_vars, host, task, play_context, self._loader, self._variable_manager, plugin_loader)
                    self._workers[self._cur_worker] = worker_prc
                    self._tqm.send_callback('v2_runner_on_start', host, task)
                    worker_prc.start()
                    display.debug("worker is %d (out of %d available)" % (self._cur_worker + 1, len(self._workers)))
                    queued = True
                self._cur_worker += 1
                if self._cur_worker >= rewind_point:
                    self._cur_worker = 0
                if queued:
                    break
                elif self._cur_worker == starting_worker:
                    time.sleep(0.0001)
            if isinstance(task, Handler):
                self._pending_handler_results += 1
            else:
                self._pending_results += 1
        except (EOFError, IOError, AssertionError) as e:
            
            display.debug("got an error while queuing: %s" % e)
            return
        display.debug("exiting _queue_task() for %s/%s" % (host.name, task.action))
    def get_task_hosts(self, iterator, task_host, task):
        if task.run_once:
            host_list = [host for host in self._hosts_cache if host not in self._tqm._unreachable_hosts]
        else:
            host_list = [task_host.name]
        return host_list
    def get_delegated_hosts(self, result, task):