class Aws::Rest::Request::QuerystringBuilder

def timestamp(ref, value)
  case ref['timestampFormat'] || ref.shape['timestampFormat']
  when 'unixTimestamp' then value.to_i
  when 'rfc822' then value.utc.httpdate
  else
    # querystring defaults to iso8601
    value.utc.iso8601
  end
end