This feature has been deprecated. Use up.Response#lateDelay instead.
up.Response#lateDelay
Load unpoly-migrate.js to polyfill deprecated features.
unpoly-migrate.js
The number of milliseconds after which this request can cause an up:network:late event and show the progress bar.
up:network:late
Defaults to up.network.config.lateDelay.
up.network.config.lateDelay
