Hi, thanks for the suggestion.
For 1), 2)will change this way.
For 3), do you mean 'event_manager->SendEvent(app_id, event)' should put under CloseAfterLoadObserver::DidFinishLoad()? If is, shall we rename SendOnInstalledEventThenWaitForReceivingAndCloseAfterThat() to WaitForReceivingAndCloseAfterThat()?