Requirements for better Xarray integration

[dcherian]

This is a tracking issue for stuff that needs to happen for better Xarray integration. For some background, see here and here

• [x] sliding_window_view for rolling:
  • [x] https://github.com/cupy/cupy/issues/6956 and https://github.com/cupy/cupy/pull/7575
  • [x] https://github.com/cupy/cupy/issues/4825
• [ ] flox support for groupby/groupby_bins/resample:
  • [ ] https://github.com/xarray-contrib/flox/issues/128 and https://github.com/cupy/cupy/issues/7561
  • [ ] also requires manual dispatching in Xarray: https://github.com/pydata/xarray/blob/ebfa77311280a15d8c455ceb5c8ddc25a2efef39/xarray/util/generate_reductions.py#L354
• [ ] Better reprs:
  • https://github.com/cupy/cupy/issues/6926;
  • An HTML repr like dask would also be nice.
  • Also a _repr_inline?
• [ ] test out & document apply_ufunc with vectorize=True (cupy already supports vectorize)
• [ ] Experiment with cuDF indexes instead of Pandas indexes