每次用户启动您的应用时，您都可以使用Transaction的currentEntitlements属性从apple documentation恢复其购买，如下面的代码所示。

func refreshPurchasedProducts() async {
    // Iterate through the user's purchased products.
    for await verificationResult in Transaction.currentEntitlements {
        switch verificationResult {
        case .verified(let transaction):
            // Check the type of product for the transaction
            // and provide access to the content as appropriate.
            ...
        case .unverified(let unverifiedTransaction, let verificationError):
            // Handle unverified transactions based on your
            // business model.
            ...
        }
    }
}

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