Sometimes I get an invalid JSON response from the API and it's not clear why (for example, a HTML error page where there would normally be a JSON body). Here's the error message I currently see:

Swish.SwishError.InvalidJSONResponse(Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.})

I think it would be useful to see the actual response decoded as a string in this case. Would that be a useful addition to Swish?