FEAT: Iterable dataset

[codingl2k1]

What do these changes do?

Implement an iterable dataset to read export dataset, it contains these features.

• [x] prefetch
• [x] retry and timeout
• [x] distributed shuffle
• [x] handle rank, world size for distributed dataset
• [x] handle worker id, num workers for multi workers dataset

Related issue number

Fixes #xxxx

Check code requirements

• [ ] tests added / passed (if needed)
• [ ] Ensure all linting tests pass

[codecov[bot]]

Codecov Report

Merging #643 (84cb627) into main (b98a556) will increase coverage by 0.03%. The diff coverage is 96.78%.

@@            Coverage Diff             @@
##             main     #643      +/-   ##
==========================================
+ Coverage   93.60%   93.64%   +0.03%     
==========================================
  Files        1024     1025       +1     
  Lines       79432    79707     +275     
  Branches    16475    16534      +59     
==========================================
+ Hits        74353    74638     +285     
+ Misses       3411     3394      -17     
- Partials     1668     1675       +7     

Flag	Coverage Δ
unittests	93.53% <96.78%> (+0.03%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
python/xorbits/datasets/iterable_dataset.py	96.70% <96.70%> (ø)
...on/xorbits/datasets/backends/huggingface/export.py	96.17% <100.00%> (+0.04%)	:arrow_up:

... and 10 files with indirect coverage changes

[aresnow1]

Have you tested on cloud storage like s3?

[codingl2k1]

Have you tested on cloud storage like s3?

Not yet. Do we have a test bucket?

[codingl2k1]

Have you tested on cloud storage like s3?

I have tested export to and read from s3. It works OK.