instance method do_parse

# File actionmailer/lib/action_mailer/vendor/tmail-1.2.7/tmail/header.rb, line 469
    def do_parse
      str = @body
      while m = MESSAGE_ID.match(str)
        pre = m.pre_match.strip
        @refs.push pre unless pre.empty?
        @refs.push s = m[0]
        @ids.push s
        str = m.post_match
      end
      str = str.strip
      @refs.push str unless str.empty?
    end