code: int pack_info(Buffer opb) {
          // preamble
          opb.write(0x01, 8);
          opb.write(_vorbis);
  
          // basic information about the stream
          opb.write(0x00, 32);
          opb.write(channels, 8);
          opb.write(rate, 32);
  
          opb.write(bitrate_upper, 32);
          opb.write(bitrate_nominal, 32);
          opb.write(bitrate_lower, 32);
  
          opb.write(Util.ilog2(blocksizes[0]), 4);
          opb.write(Util.ilog2(blocksizes[1]), 4);
          opb.write(1, 1);
          return (0);
      }
docs: pack side