Payment method tokenization types.
Available options:
WalletConstants.PAYMENT_METHOD_TOKENIZATION_TYPE_PAYMENT_GATEWAY
WalletConstants.PAYMENT_METHOD_TOKENIZATION_TYPE_NETWORK_TOKEN
WalletConstants.PAYMENT_METHOD_TOKENIZATION_TYPE_DIRECTIntegrator can configure PaymentDataRequest
to tokenize the credit card selected by the buyer for a transaction using one of the
tokenization types listed above. The token for the selected payment method can be retrieved
by calling PaymentData.getPaymentMethodToken().