awaitSyncPurchases
This method will send all the purchases to the RevenueCat backend. Call this when using your own implementation for subscriptions anytime a sync is needed, such as when migrating existing users to RevenueCat.
Coroutine friendly version of Purchases.syncPurchases.
Return
The CustomerInfo associated to the user, after all purchases have been successfully synced. If there are no purchases to sync, the customer info will be returned without any changes.
Throws
with the first PurchasesError found while syncing the purchases.