open_consolidated doesn't accept enough kwargs

[rabernat]

Minimal, reproducible code sample, a copy-pastable example if possible

open_consolidated doesn't accept the same keywords as open_group. This makes it hard to replace open_group with open_consolidated in downstream code (e.g. xarray).

# create a new store
path = 'consolidated-test.zarr'
new_group = zarr.open_group(path, mode='w', synchronizer=None)
a = new_group.create('foo', shape=(10,))
zarr.consolidate_metadata(new_group.store)
group_cons = zarr.open_consolidated(path, mode='r', synchronizer=None)

gives the error

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-17-1eea689b4531> in <module>()
      3 a = new_group.create('foo', shape=(10,))
      4 zarr.consolidate_metadata(new_group.store)
----> 5 group_cons = zarr.open_consolidated(path, mode='r', synchronizer=None)

TypeError: open_consolidated() got an unexpected keyword argument 'synchronizer'

Problem description

The open_consolidated convenience function should pass through any arguments to the underlying open method. Instead, it does this

https://github.com/zarr-developers/zarr/blob/e44c4c5951181c86cc54998d4ddeb221f8059e72/zarr/convenience.py#L1181-L1185

Contrast this with open:

https://github.com/zarr-developers/zarr/blob/e44c4c5951181c86cc54998d4ddeb221f8059e72/zarr/convenience.py#L22-L36

Version and installation information

Zarr version is '2.2.1.dev97'

[alimanfoo]

Thanks @rabernat. Should be fine I think to add **kwargs to the signature for open_consolidated() and pass through to open().

[rabernat]

Just some discussion... I have been thinking about how to best integrate with xarray. I am wondering about the choice to add a new convenience method open_consolidated rather than add a consolidated keyword to the existing convenience method open. Do we really want to maintain two separate open functions?

I know I should have raised this question during the review, but it didn't occur to me until I started working on the xarray integration issue.

[alimanfoo]

FWIW I think I preferred a separate function because it kept the consolidated API separate for now, and so could be clearly marked as experimental. Also if you add in a consolidated argument to open() then you also need to add in another argument to allow user to specify the metadata key where the consolidated metadata is stored, which is obviously only relevant sometimes, so there's a bit more complexity to argument handling. These are minor points, I would be happy to revisit in future.