Step 1 of the two-step Apple Pay flow.
Creates a pending Apple Pay transaction and returns its transactionId
before the Apple Pay sheet is shown to the user.
Use the returned transactionId together with the payment token obtained
from the wallet authorization in finalizeApplePayPayment.
Step 1 of the two-step Apple Pay flow. Creates a pending Apple Pay transaction and returns its
transactionIdbefore the Apple Pay sheet is shown to the user.Use the returned
transactionIdtogether with the payment token obtained from the wallet authorization infinalizeApplePayPayment.iOS only.