code: func Quantize(buf *audio.PCMBuffer, bitDepth int) {
  	if buf == nil {
  		return
  	}
  	max := math.Pow(2, float64(bitDepth)) - 1
  
  	buf.SwitchPrimaryType(audio.Float)
  	bufLen := buf.Len()
  	for i := 0; i < bufLen; i++ {
  		buf.Floats[i] = round((buf.Floats[i]+1)*max)/max - 1.0
  	}
  }
docs: // Quantize quantizes the audio signal to match the target bitDepth