Xandra does not allow to wait for schema ageement/consensus after (maybe also before) executing schema changes.
Cassandra exports schema_version on system.peers and system.local tables, and some Cassandra database drivers allow to wait for consensus/schema agreement.
This feature seems to be required when executing migrations between different schema versions on Cassandra clusters.

1. Are pull requests with this feature going to be accepted?
2. Should this API be implemented as an additional module built on top of existing Xandra modules, or should the driver hide this detail to the end user?