presto-jdbc/src/main/java/io/prestosql/jdbc/PrestoStatement.java/PrestoStatement/partialCancel
class PrestoStatement:    public void partialCancel()
            throws SQLException
    {
        checkOpen();

        StatementClient client = executingClient.get();
        if (client != null) {
            client.cancelLeafStage();
        }
        else {
            PrestoResultSet resultSet = currentResult.get();
            if (resultSet != null) {
                resultSet.partialCancel();
            }
        }
    }