Is there a way to download only NQ dev?
Maybe I missed that in the docs, but is there a way to only download the dev set of natural questions (~1 GB)? 
As we want to benchmark QA models on different datasets, I would like to avoid downloading the 41GB of training data. 

I tried
```
dataset = nlp.load_dataset('natural_questions', split="validation", beam_runner="DirectRunner")
```
But this still triggered a big download of presumably the whole dataset. Is there any way of doing this or are splits / slicing options only available after downloading?

Thanks!