apollo-client-config-data/src/main/java/com/ctrip/framework/apollo/config/data/listener/ApolloDeferredLoggerApplicationListener.java/ApolloDeferredLoggerApplicationListener/onApplicationEvent
class ApolloDeferredLoggerApplicationListener:  @Override
  public void onApplicationEvent(SpringApplicationEvent event) {
    if (event instanceof ApplicationContextInitializedEvent) {
      DeferredLogger.replayTo();
    }
    if (event instanceof ApplicationFailedEvent) {
      DeferredLogger.replayTo();
    }
  }