7 files declare their use of TransactionIsolationLevel in Drupal driver for SQL Server and SQL Azure 8

Connection.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Connection.php

Definition of Drupal\Driver\Database\sqlsrv\Connection

Insert.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Insert.php

Definition of Drupal\Driver\Database\sqlsrv\Insert

Merge.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Merge.php

Definition of Drupal\Driver\Database\sqlsrv\Merge

Schema.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Schema.php

Definition of Drupal\Driver\Database\sqlsrv\Schema

Transaction.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Transaction.php

Definition of Drupal\Driver\Database\sqlsrv\Transaction

TransactionSettings.php in drivers/lib/Drupal/Driver/Database/sqlsrv/TransactionSettings.php

Update.php in drivers/lib/Drupal/Driver/Database/sqlsrv/Update.php

Definition of Drupal\Driver\Database\sqlsrv\Update