Validate status code with TextToSpeech.synthesize()
Validate status code with TextToSpeech.synthesize()

If credentials are invalid, then the service will not return a valid 200 status code. By explicitly validating the service code, we can avoid accidentally trying to parse the error response associated with invalid credentials as a WAV file.

tad-iizuka/swift-sdk,tad-iizuka/swift-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,tad-iizuka/swift-sdk,watson-developer-cloud/ios-sdk,tad-iizuka/swift-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,tad-iizuka/swift-sdk