class Rack::Session::Abstract::Persisted

def commit_session(req, res)
  session = req.get_header RACK_SESSION
  options = session.options
  if options[:drop] || options[:renew]
    session_id = delete_session(req, session.id || generate_sid, options)
    return unless session_id
  end
  return unless commit_session?(req, session, options)
  session.send(:load!) unless loaded_session?(session)
  session_id ||= session.id
  session_data = session.to_hash.delete_if { |k, v| v.nil? }
  if not data = write_session(req, session_id, session_data, options)
    req.get_header(RACK_ERRORS).puts("Warning! #{self.class.name} failed to save session. Content dropped.")
  elsif options[:defer] and not options[:renew]
    req.get_header(RACK_ERRORS).puts("Deferring cookie for #{session_id}") if $VERBOSE
  else
    cookie = Hash.new
    cookie[:value] = cookie_value(data)
    cookie[:expires] = Time.now + options[:expire_after] if options[:expire_after]
    cookie[:expires] = Time.now + options[:max_age] if options[:max_age]
    if @same_site.respond_to? :call
      cookie[:same_site] = @same_site.call(req, res)
    else
      cookie[:same_site] = @same_site
    end
    set_cookie(req, res, cookie.merge!(options))
  end
end