static var shared: Purchases Returns the already configured instance of
Purchases.static var isConfigured : Bool Returns
true if RevenueCat has already been initialized through configure(withAPIKey:) or one of is overloads.var delegate: PurchasesDelegate ? Delegate for
Purchases instance. The delegate is responsible for handling promotional product purchases and changes to customer information.static var logHandler : LogHandler Set a custom log handler for redirecting logs to your own logging system.