code: public Future<Void> setKeyspace(CqlIdentifier newKeyspace) {
      Promise<Void> promise = channel.eventLoop().newPromise();
      channel.pipeline().fireUserEventTriggered(new SetKeyspaceEvent(newKeyspace, promise));
      return promise;
    }
docs: Switches the underlying Cassandra connection to a new keyspace (as if a {@code USE ...}
  statement was issued).
  
  <p>The future will complete once the change is effective. Only one change may run at a given
  time, concurrent attempts will fail.
  
  <p>Changing the keyspace is inherently thread-unsafe: if other queries are running at the same
  time, the keyspace they will use is unpredictable.