presto-cassandra/src/main/java/io/prestosql/plugin/cassandra/CassandraTokenSplitManager.java/CassandraTokenSplitManager/TokenSplit
class CassandraTokenSplitManager:        public TokenSplit(String startToken, String endToken, List<String> hosts)
        {
            this.startToken = requireNonNull(startToken, "startToken is null");
            this.endToken = requireNonNull(endToken, "endToken is null");
            this.hosts = ImmutableList.copyOf(requireNonNull(hosts, "hosts is null"));
        }