presto-cassandra/src/main/java/io/prestosql/plugin/cassandra/CassandraTokenSplitManager.java/CassandraTokenSplitManager/createSplit
class CassandraTokenSplitManager:    private static TokenSplit createSplit(TokenRange range, List<String> endpoints)
    {
        checkArgument(!range.isEmpty(), "tokenRange must not be empty");
        String startToken = range.getStart().toString();
        String endToken = range.getEnd().toString();
        return new TokenSplit(startToken, endToken, endpoints);
    }