Text-to-speech not working when using Java API - dialogflow-es

Question

So, I have text-to-speech turned on, plus the "enable beta features and API" on. On the DialogFlow web page where you can add intents and test them, the feature is working and I get a small audio control where I can hear the audio corresponding to the fullfilment text.
But, when I try to get the audio via the Java API, I'm not getting it. The code below will produce the following output:
>2018-07-30 02:26:53 mmcsrv.agent.SpeechIntentDetector: response_id
>
2018-07-30 02:26:53 mmcsrv.agent.SpeechIntentDetector: query_result
>
2018-07-30 02:26:53 mmcsrv.agent.SpeechIntentDetector: webhook_status
I'd expect to find output_audio field in there but it's not, so where is the audio ?
My Maven for this module:
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-dialogflow</artifactId>
<version>0.53.0-alpha</version>
</dependency>
I tried 0.55.1-alpha but Maven says it doesn't exist. Not sure if not using the latest version would matter anyway.
Can someone help me ? If I can't get this to work, I'll have to send the text back to Google Cloud text-to-speech which I'm guessing will take more time than to have the audio data right there in Dialogflow's response.
Thanks.
// Details omitted for brevity...
// Build the DetectIntentRequest
DetectIntentRequest request = DetectIntentRequest.newBuilder()
.setSession(session.toString())
.setQueryInput(queryInput)
.setInputAudio(wav)
.build();
// Performs the detect intent request
DetectIntentResponse resp = sessionsClient.detectIntent(request);
List<FieldDescriptor> fields = resp.getDescriptorForType().getFields();
for (FieldDescriptor field : fields )
log.trace(field.getName());

Answer 1

To answer my own question,
Dialogflow does send the audio, but you need the correct protobuffer proxy to be able to get it. If you're using Maven like me, version 0.53.0-alpha of artifact google-cloud-dialogflow pulls version 0.18.0 of proto-google-cloud-dialogflow-v2beta1 which has a proxy that does not yet has text-to-speech support.
You need to add version 0.20.1 or above by adding the this snippet to your pom file:
<dependency>
<groupId>com.google.api.grpc</groupId>
<artifactId>proto-google-cloud-dialogflow-v2beta1</artifactId>
<version>0.20.1</version>
Once you do that, class DetectIntentResponse will have the method getOutputAudio() that will give you the audio data.
I have it working now.