Help using ExportAudioToWavFileTask to export multiple audio streams as one .wav file

Hi, I'm using this teams bot to record call audio for multiple people in MS Teams. I've been able to export each stream to it's own .wav, but I want to export them all to one file that accurately recreates the audio from the teams call. I tried using ExportAudioToWaveFileTask but I am clearly using it wrong. Here's my code, which currently throws System.Exception: 'Stream specification not found: Audio' on the last line

        const string storeName = "test_audio";
        const string path = "C:\\\\store";
        string filePath = Path.Join(path, storeName);
        using Pipeline pipeline = Pipeline.Create();
        PsiStoreStreamReader reader = new PsiStoreStreamReader(storeName, path);
        PsiExporter exporter = PsiStore.Create(pipeline, $"{storeName}_temp", null, false, null);
        var streams = reader.AvailableStreams;
        Dataset dataset = Dataset.CreateAsync(reader).Result;
        dataset.AddSessionAsync(reader);
        ExportAudioToWavFileTask task = new ExportAudioToWavFileTask{};
        var config = new ExportAudioToWavFileTaskConfiguration();
        SessionImporter sessionImporter = SessionImporter.Open(pipeline, dataset.Sessions.First());
        
        task.Run(pipeline, sessionImporter, exporter, config);

Start with the ExportAudioToWavFileTask API documentation and the Microsoft Graph PsiBot sample, then inspect the ExportAudioToWavFileTaskConfiguration and SessionImporter usage in the provided code. Determine how the audio stream specification should represent multiple streams; done means the task exports them as one WAV file without the “Stream specification not found: Audio” exception.