A class that presents the individual steps of a payment sheet flow.
Configure the FlowController to process a PaymentIntent.
Configure the FlowController to process a SetupIntent.
Complete the payment or setup.
Retrieve information about the customer's desired payment option. You can use this to e.g. display the payment option in your UI.
Present a sheet where the customer chooses how to pay, either by selecting an existing payment method or adding a new one. Call this when your "Select a payment method" button is tapped.