transactionIdentifier property
The unique string identifer of the transaction.
It is only defined when the transactionState is SKPaymentTransactionStateWrapper.purchased or SKPaymentTransactionStateWrapper.restored. You may wish to record this string as part of an audit trail for App Store purchases. The value of this string corresponds to the same property in the receipt.
The value is null if it is an unsuccessful transaction.
Implementation
final String? transactionIdentifier;