Improve detection of streamable file types
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maybe we should rather attempt to download a `Range` from the server and see if it works?
2021-08-02T16:35:49Z
https://github.com/huggingface/datasets/issues/2742#issuecomment-891167456
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2021-08-02T16:35:49Z
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**Is your feature request related to a problem? Please describe.**

```python
from datasets import load_dataset_builder
from datasets.utils.streaming_download_manager import StreamingDownloadManager
builder = load_dataset_builder("journalists_questions", name="plain_text")
builder._split_generators(StreamingDownloadManager(base_path=builder.base_path))
```

raises

```
NotImplementedError: Extraction protocol for file at https://drive.google.com/uc?export=download&id=1CBrh-9OrSpKmPQBxTK_ji6mq6WTN_U9U is not implemented yet
```

But the file at https://drive.google.com/uc?export=download&id=1CBrh-9OrSpKmPQBxTK_ji6mq6WTN_U9U is a text file and it can be streamed:

```bash
curl --header "Range: bytes=0-100" -L https://drive.google.com/uc\?export\=download\&id\=1CBrh-9OrSpKmPQBxTK_ji6mq6WTN_U9U
506938088174940160      yes     1
302221719412830209      yes     1
289761704907268096      yes     1
513820885032378369      yes     %
```

Yet, it's wrongly categorized as a file type that cannot be streamed because the test is currently based on 1. the presence of a file extension at the end of the URL (here: no extension), and 2. the inclusion of this extension in a list of supported formats.

**Describe the solution you'd like**

In the case of an URL (instead of a local path), ask for the MIME type, and decide on that value? Note that it would not work in that case, because the value of `content_type` is `text/html; charset=UTF-8`.

**Describe alternatives you've considered**

Add a variable in the dataset script to set the data format by hand.
