code: func GnuplotBin(buf *audio.PCMBuffer, path string) error {
  	if buf == nil || buf.Format == nil {
  		return audio.ErrInvalidBuffer
  	}
  	out, err := os.Create(path)
  	if err != nil {
  		return err
  	}
  	defer out.Close()
  	for _, s := range buf.AsFloat32s() {
  		if err = binary.Write(out, binary.BigEndian, s); err != nil {
  			break
  		}
  	}
  	return err
  }
docs: // GnuplotBin exports the buffer content as a binary gnuplot file.