presto-example-http/src/main/java/io/prestosql/plugin/example/ExampleRecordCursor.java/ExampleRecordCursor/getSlice
class ExampleRecordCursor:    @Override
    public Slice getSlice(int field)
    {
        checkFieldType(field, createUnboundedVarcharType());
        return Slices.utf8Slice(getFieldValue(field));
    }