code: @Override
    public long skip(long n)
      throws IOException
    {
      if (_is == null) {
        if (_s == null)
          return -1;
  
        _is = _s.getInputStream();
      }
  
      return _is.skip(n);
    }
docs: Skips bytes in the file.
  
  @param n the number of bytes to skip
  
  @return the actual bytes skipped.