Update README.md

README.md

@@ -2,7 +2,7 @@
 
 A simple In-App Purchase plugin for Xamarin and Windows to query item information, purchase items, restore items, and more.
 
-## Documentation
+## 2.0/3.0 Documentation
 Get started by reading through the [In-App Billing Plugin documentation](https://jamesmontemagno.github.io/InAppBillingPlugin/).
 
 ## NuGet
@@ -37,6 +37,12 @@ Version 4.X updates to the new Android billing client. This means there are few
 1.) You must acknowledge all purchases within 3 days, by calling `AcknowledgePurchaseAsync` or the Consume API if it a consumable.
 2.) You must hanle Pending Transactions from outside of you app. See [docs from Google](https://developer.android.com/google/play/billing/integrate#pending)
 
+### Pending Transactions:
+* If the result of PurchaseAsync is PurchaseState.PaymentPending, store the order details locally and inform the user that they will have access to the product when the payment completes
+* When the user starts the app (and/or visits a particular page), if the stored PurchaseState is PaymentPending, call GetPurchasesAsync and query the result for a purchase that matches the stored purchase.
+* If the PurchaseState for this purchase is still PaymentPending, show the same no-access message
+* If the PurchaseState is Purchased, call ConsumePurchaseAsync or AcknowledgePurchaseAsync, depending on the product type
+
 I highly recommend reading the entire [Google Play Billing System docs](https://developer.android.com/google/play/billing/).
 
 ## Version 3+ Linker Settings