code: def dump(io)
        bytes_written = 0
        @entries.each do |entry|
          bytes_written += entry.dump_local_file_record(io, bytes_written)
        end
        central_directory_offset = bytes_written
        @entries.each do |entry|
          bytes_written += entry.dump_central_file_record(io)
        end
        central_directory_length = bytes_written - central_directory_offset
        bytes_written += io.write(EOCD_SIGNATURE)
        bytes_written += io.write(
          [
            0,
            0,
            @entries.length,
            @entries.length,
            central_directory_length,
            central_directory_offset,
            comment.bytesize
          ].pack('vvvvVVv')
        )
        bytes_written += io.write(comment)
  
        bytes_written
      end
docs: Writes all the entries of this archive to _io_.  _io_ must be a writable,
   IO-like object providing a _write_ method.  Returns the total number of
   bytes written.