def type_params
    result = {}
    list = self['Content-Type'].to_s.split(';')
    list.shift
    list.each do |param|
      k, v = *param.split('=', 2)
      result[k.strip] = v.strip
    end
    result
  end
Any parameters specified for the content type, returned as a Hash.
For example, a header of Content-Type: text/html; charset=EUC-JP
would result in type_params returning {'charset' => 'EUC-JP'}