@SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public static WatchServiceConfiguration polling(long interval, TimeUnit timeUnit) {
    return new PollingConfig(interval, timeUnit);
  }
Returns a configuration for a {@link WatchService} that polls watched directories for changes
every {@code interval} of the given {@code timeUnit} (e.g. every 5 {@link TimeUnit#SECONDS
seconds}).
jimfs/src/main/java/com/google/common/jimfs/WatchServiceConfiguration.java