public async Task <TransactionResponse> SubmitPrimaryTransactionAsync(PrimaryTransaction payload, string region = null)
{
Signature signatureService = GetSignatureService();
string messageSignature = signatureService.Sign(JsonConvert.SerializeObject(payload));
return(await payApi.SubmitPrimaryTransactionAsync(
CONTENT_TYPE,
signatureService.ClientRequestId,
GetApiKey(),
signatureService.TimeStamp,
payload,
messageSignature,
region
));
}