public B keyspace(String keyspace) {
    if (keyspace == null) throw new NullPointerException("keyspace == null");
    this.keyspace = keyspace;
    return (B) this;
  }
Keyspace to store span and index data. Defaults to "zipkin3"
zipkin-storage/cassandra/src/main/java/zipkin2/storage/cassandra/CassandraStorageBuilder.java