public static <T> RemoteIterator<T> remoteIteratorFromSingleton(
      @Nullable T singleton) {
    return new SingletonIterator<>(singleton);
  }
@Test
  public void testSingletonStats() throws Throwable {
    IOStatsInstance singleton = new IOStatsInstance();
    RemoteIterator<IOStatsInstance> it
        = remoteIteratorFromSingleton(singleton);
    extractStatistics(it);
  }