code: private void writeChunkMetaData(final BAMIndexMetaData metaData) {
        codec.writeInt(GenomicIndexUtil.MAX_BINS);
        final int nChunk = 2;
        codec.writeInt(nChunk);
        codec.writeLong(metaData.getFirstOffset());
        codec.writeLong(metaData.getLastOffset());
        codec.writeLong(metaData.getAlignedRecordCount());
        codec.writeLong(metaData.getUnalignedRecordCount());
  
    }
docs: Write the meta data represented by the chunkLists associated with bin MAX_BINS 37450
  
  @param metaData information describing numAligned records, numUnAligned, etc