public static <T extends Serializable> ItemImportResult<T> success(T data, Long sizeInBytes) {
    Preconditions.checkNotNull(data);
    return new ItemImportResult<>(data, sizeInBytes, Status.SUCCESS, null);
  }
@Test
  public void testSuccessWithNoData() {
    assertThrows(NullPointerException.class, () -> {
      ItemImportResult.success(null, 0L);
    });
  }