apollo-client/src/main/java/com/ctrip/framework/apollo/internals/RemoteConfigLongPollService.java/RemoteConfigLongPollService/updateNotifications
class RemoteConfigLongPollService:  private void updateNotifications(List<ApolloConfigNotification> deltaNotifications) {
    for (ApolloConfigNotification notification : deltaNotifications) {
      if (Strings.isNullOrEmpty(notification.getNamespaceName())) {
        continue;
      }
      String namespaceName = notification.getNamespaceName();
      if (m_notifications.containsKey(namespaceName)) {
        m_notifications.put(namespaceName, notification.getNotificationId());
      }
      //since .properties are filtered out by default, so we need to check if there is notification with .properties suffix
      String namespaceNameWithPropertiesSuffix =
          String.format("%s.%s", namespaceName, ConfigFileFormat.Properties.getValue());
      if (m_notifications.containsKey(namespaceNameWithPropertiesSuffix)) {
        m_notifications.put(namespaceNameWithPropertiesSuffix, notification.getNotificationId());
      }
    }
  }