Need way to support multiple Merchant Authentication credentials in one application #160

Good morning!

I'm running into an issue that we can not configure multiple merchant authentication details because ApiOperationBase declares the MerchantAuthenticationType as static. It seems that it behaves this way as "convenience" so that every request object doesn't need have them set, but in my case I need it to be composed in the object rather than declared static.

The only other solution I can come up with for using this SDK for our application would be to synchronize the set of ApiOperationBase.setMerchantAuthentication(), request creation, and request sending all in one block, which would greatly bottleneck the application.

Is there another way you would suggest handling this use case?

Thanks so much for your time and a timely response would be much appreciated.