to_dbal_transaction

/**
 * Write every child within database transactions.
 * Each batch of rows is written in its own transaction; rows a branch's Transformation delivers when
 * the run ends (blocking operations drain there) are committed in one final transaction.
 * If any write fails, the open transaction is rolled back.
 * A plain Loader child is written directly; a to_transformation(...) child delivers inside the same
 * transaction. Every child's loader must use the same connection as the transaction: pass one live
 * Connection to both - a loader built from array params opens its own connection and escapes the
 * transaction.
 *
 * @param array<string, mixed>|Connection $connection
 * @param Loader|Branch ...$writes - written within the transaction
 *
 * @throws InvalidArgumentException
 */
to_dbal_transaction(Connection|array $connection, Loader|Branch $writes) : Transactional