Preloads this link when the user hovers over it.
When the link is clicked later the response will already be cached, making the interaction feel instant.
Preloading a link will not abort pending requests targeting the same fragments. Only when the link is clicked later conflicting requests are aborted.
Preload requests are considered background requests and will not show the progress bar.
The number of milliseconds to wait between hovering and preloading. Increasing this will lower the load in your server, but will also make the interaction feel less instant.