private void onAudioConfigChanged(byte[] address, int sampleRate, int channelCount) {
   StackEvent event = new StackEvent(EVENT_TYPE_AUDIO_CONFIG_CHANGED);
   int channelConfig =
       (channelCount == 1 ? AudioFormat.CHANNEL_IN_MONO : AudioFormat.CHANNEL_IN_STEREO);
   event.audioConfig =
       new BluetoothAudioConfig(sampleRate, channelConfig, AudioFormat.ENCODING_PCM_16BIT);
   event.device = getDevice(address);
   sendMessage(STACK_EVENT, event);
 }