presto-kudu/src/main/java/io/prestosql/plugin/kudu/KuduConnector.java/KuduConnector/beginTransaction
class KuduConnector:    @Override
    public ConnectorTransactionHandle beginTransaction(IsolationLevel isolationLevel, boolean readOnly)
    {
        checkConnectorSupports(READ_COMMITTED, isolationLevel);
        return KuduTransactionHandle.INSTANCE;
    }