code: void checkLostBlocks(List<Block> blocksLostChecksum,
        List<Block> blocksLostStripe, Path p, Codec codec)
        throws IOException {
      StringBuilder message = new StringBuilder();
      if (blocksLostChecksum.size() > 0) {
        message.append("Lost " + blocksLostChecksum.size() +
            " checksums in blocks:");
        for (Block blk : blocksLostChecksum) {
          message.append(" ");
          message.append(blk.toString());
        }
      }
      if (blocksLostStripe.size() > 0) {
        message.append("Lost " + blocksLostStripe.size() +
            " stripes in blocks:");
        for (Block blk : blocksLostStripe) {
          message.append(" ");
          message.append(blk.toString());
        }
      }
      if (message.length() == 0)
        return;
      message.append(" in file " + p);
      throw new IOException(message.toString());
    }
docs: Throw exceptions for blocks with lost checksums or stripes