Client configuration is null when specifying bucket configs in ClientConfiguration

var config = new ClientConfiguration

{

    Servers = new List<Uri> {new Uri("http://localhost:8091/pools")},

    BucketConfigs = new Dictionary<string, BucketConfiguration>

    {

        {"default", new BucketConfiguration {UseKvErrorMap = true}}

    }

};

var cluster = new Cluster(config);

cluster.OpenBucket("default");