Documents prefetched by design?

[eeng]

Recently in an application of ours, we've been receiving bursts of requests to PDF documents which were causing some problems. It turned out some of our users were using this extension so when they entered some pages that contain many links to PDFs the extension would prefetch them all producing that burst we were seeing. The problem has been solved but I just wanted to know if this prefetching is by design. If it is not necessary for the normal functioning of the plugin, It seems to me that it would be better to provide it as an option to the user. Maybe users with a slow Internet connection would opt out of it to prevent consuming that extra bandwidth. Anyway, just a suggestion. Keep up the good work.