toAppsFlyerEventValues
The event values for af_purchase: AppsFlyerPurchaseEvent.parameters, then the predefined ones. An absent optional is left out rather than sent empty. Public because a custom AppsFlyerEventTracker almost always needs it.
Throws an IllegalArgumentException if a parameter has a key the purchase sets itself.
The event values for af_subscribe: AppsFlyerSubscribeEvent.parameters, then the predefined ones. Public because a custom AppsFlyerEventTracker almost always needs it.
Throws an IllegalArgumentException if a parameter has a key the subscription sets itself.
Event parameters as AppsFlyer event values; see asAppsFlyerValue.