private void DrainAudio()
        {
            _numSamples = QN.qn_read_audio(Context, _monoBuff, _monoBuff.Length);
            unsafe
            {
                fixed(short *_src = &_monoBuff[0], _dst = &_stereoBuff[0])
                {
                    short *src = _src;
                    short *dst = _dst;

                    for (int i = 0; i < _numSamples; i++)
                    {
                        *dst++ = *src;
                        *dst++ = *src++;
                    }
                }
            }
        }