docs: void fileWritten() throws ConfigurationPersistenceException {
          if (!doneBootup.get() || interactionPolicy.isReadOnly()) {
              return;
          }
          try {
              FilePersistenceUtils.copyFile(mainFile, lastFile);
          } catch (IOException e) {
              throw ControllerLogger.ROOT_LOGGER.failedToBackup(e, mainFile);
          }
      }