Keytransform Only Supports Batched Datastores

[bonedaddy]

I'm working on a codebase that currently uses a datastore.Batching type backed by leveldb using a namespace wrap. Unfortunately it appears that the namespace only supports datastore.Batching and can't be used in place of a datastore.TxnDatastore.

Is this intentional?

[Stebalien]

We should probably be doing what we do in the mount datastore. There, we type assert to datastore.Batching on demand and return ds.ErrBatchUnsupported if batching is unsupported.