Zarr's top level API is the primary entrypoint for users to interact with Zarr objects. Stuff like:

• zarr.open
• zarr.zeros, zarr.ones, zarr.empty
• zarr.load, zarr.save
• zarr.array, zarr.group

This API needs to be wired up to the new Array and Group classes in the v3 dev branch. We should definitely attempt to keep these all close to the same API but v3 will give us the chance to rework these if there is a strong reason to do so.