internal PaymentMethodTokenRecipient(string recipientId, ISignatureKeyProvider signatureKeyProvider, Util.IClock clock)
 {
     _recipientId           = recipientId;
     _signatureKeyProvider  = signatureKeyProvider;
     _signatureVerification = new SignatureVerification(clock);
 }
 /// <param name="recipientId">Your recipient_id, as provided by Google</param>
 /// <param name="signatureKeyProvider">Provider of public keys for ECDSA signature verification</param>
 public PaymentMethodTokenRecipient(string recipientId, ISignatureKeyProvider signatureKeyProvider)
 {
     _recipientId          = recipientId;
     _signatureKeyProvider = signatureKeyProvider;
 }