Zarr has its own internal mechanism for caching, described here:

• https://zarr.readthedocs.io/en/stable/tutorial.html#distributed-cloud-storage
• https://zarr.readthedocs.io/en/stable/api/storage.html#zarr.storage.LRUStoreCache

However, this capability is currently inaccessible from xarray.

I propose to add a new keyword cache=True/False to open_zarr which wraps the store in an LRUStoreCache.