code: @Override
    public INodeRaidStorage convertToRaidStorage(BlockInfo[] parityBlocks, 
        RaidCodec codec, int[] checksums, BlocksMap blocksMap, short replication,
        INodeFile inode) throws IOException {
      if (codec == null) {
        throw new IOException("Codec is null");
      } else {
        return new INodeRaidStorage(codec.convertToRaidStorage(parityBlocks,
            blocks, checksums, blocksMap, replication, inode), codec);
      }
    }
docs: Only used by merge, it puts parity file's blocks and source file's blocks
  together into a block array to create an INodeRaidStorage