lastStatements property

If set to true, this request marks the end of the transaction.

After these statements execute, you must commit or abort the transaction. Attempts to execute any other requests against this transaction (including reads and queries) are rejected. Setting this option might cause some error reporting to be deferred until commit time (for example, validation of unique constraints). Given this, successful execution of statements shouldn't be assumed until a subsequent Commit call completes successfully.

Optional.