title: Calling SKPaymentQueue restoreCompletedTransactions, no response
body: <p>The use case here is that the user has never purchased my in-app purchase but taps the Restore button. I want to let the user know that the restore has failed because there is nothing to restore.</p>
  
  <p>The problem is that I'm not getting any event. So I don't know that anything has happened.</p>
  
  <p>When my user taps the Restore button in my interface, I call</p>
  
  <pre><code>SKPaymentQueue.default().restoreCompletedTransactions
  </code></pre>
  
  <p>However, after that nothing is happening. I expect my SKPaymentTransactionObserver <code>paymentQueue(_:updatedTransactions:)</code> to be called, but it isn't.</p>
  
  <p>I tried implementing <code>paymentQueue(_:restoreCompletedTransactionsFailedWithError:)</code>, but it isn't being called either.</p>