Get Audio bytes when `ReceiveUnmixedMeetingAudio` is set to `true`

I am working on a bot that is supposed to attend group calls/online meetings. The bot needs to access audio spoken by each participant that will be send to transcription service at the end of the meeting. In CallHandler.cs we can add an event handler OnAudioMediaReceived(object sender, AudioMediaReceivedEventArgs e), where we can get the audio buffers for each speaker. My question is, where can I find the byte array against each speaker. When event handler is fired e.Buffer.Data always returns '0's while there are audio bytes in e.Buffer.UnmixedAudioBuffers[0].Data. So I am creating a byte array out of it and adding that to a generic list which will be parsed once the meeting is ended, to generate the transcript:

byte[] managedByteArray = new byte[e.Buffer.UnmixedAudioBuffers[0].Length];
                  int length = (int)e.Buffer.UnmixedAudioBuffers[0].Length;
                  Marshal.Copy(e.Buffer.UnmixedAudioBuffers[0].Data, managedByteArray, 0, length);
                  this.AudioByteArrayList.Add(managedByteArray);

I just want to make sure that am I getting the audio bytes in a correct way? as I am not getting desired results from speech to text service ( I am using cognitive speech service provided by Microsoft for transcription) .

Start with CallHandler.cs and the OnAudioMediaReceived handler, comparing e.Buffer.Data with e.Buffer.UnmixedAudioBuffers[0].Data and the reported lengths. Determine which buffer and audio representation should be supplied to the Microsoft speech-to-text service, and document what confirms that the extracted bytes are valid for transcription.