code: @Override
      public FileMonitorService createFileMonitorService() {
          long pollingIntervalMillis = getPollingTimeUnit().toMillis(getPollingInterval());
          FileAlterationMonitor fileAlterationMonitor = new FileAlterationMonitor(pollingIntervalMillis);
          return new CommonsIOFileMonitorServiceImpl(fileAlterationMonitor);
      }
docs: Creates a new {@link CommonsIOFileMonitorServiceImpl}.
  @param pollingInterval the polling interval
  @param pollingTimeUnit the time unit for the polling interval.
  @return a new {@link CommonsIOFileMonitorServiceImpl}, which wraps a
  newly-created {@link FileAlterationMonitor}