Dataset is slower after calling `to_iterable_dataset`

### Describe the bug

Can anyone explain why looping over a dataset becomes slower after calling `to_iterable_dataset` to convert to `IterableDataset`

### Steps to reproduce the bug

Any dataset after converting to `IterableDataset`

### Expected behavior

Maybe it should be faster on big dataset? I only test on small dataset

### Environment info

- `datasets` version: 2.14.4
- Platform: Linux-5.15.0-76-generic-x86_64-with-glibc2.17
- Python version: 3.8.15
- Huggingface_hub version: 0.16.4
- PyArrow version: 12.0.1
- Pandas version: 1.5.3