The Transaction#begin is important for a JPA provider perspective as we can build a transaction context. However, for RL, there is no equivalent on the Connection interface, and so we just call the auto-commit to false:

getConnectionForTransactionManagement().setAutoCommit( false );

However, to quote the JavaDocs:

If setAutoCommit is called and the auto-commit mode is not changed, the call is a no-op.