presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/metadata/ShardIterator.java/ShardIterator/close
class ShardIterator:    @SuppressWarnings({"UnusedDeclaration", "EmptyTryBlock"})
    @Override
    public void close()
    {
        // use try-with-resources to close everything properly
        try (Connection connection = this.connection;
                Statement statement = this.statement;
                ResultSet resultSet = this.resultSet) {
            // do nothing
        }
        catch (SQLException ignored) {
        }
    }