def _dump(limit)
    Marshal.dump [
      @rubygems_version,
      @specification_version,
      @name,
      @version,
      date,
      @summary,
      @required_ruby_version,
      @required_rubygems_version,
      @original_platform,
      @dependencies,
      @rubyforge_project,
      @email,
      @authors,
      @description,
      @homepage,
      true, # has_rdoc
      @new_platform,
      @licenses
    ]
  end
#
Dump only crucial instance variables.
--
MAINTAIN ORDER!
(down with the man)