presto-local-file/src/main/java/io/prestosql/plugin/localfile/LocalFileRecordCursor.java/LocalFileRecordCursor/getFieldValue
class LocalFileRecordCursor:    private String getFieldValue(int field)
    {
        checkState(fields != null, "Cursor has not been advanced yet");

        int columnIndex = fieldToColumnIndex[field];
        if (columnIndex == SERVER_ADDRESS_ORDINAL_POSITION) {
            return address.toString();
        }
        if (columnIndex >= fields.size()) {
            return null;
        }
        return fields.get(columnIndex);
    }