[Octane]

А с воркером так точно нельзя? Mozilla ни одной лазейки не оставила?

https://developer.mozilla.org/en-US/..._API_reference

A Service Worker inherits all the limitations and behaviors available to HTML5 Shared Workers. It can create XMLHttpRequests, use WebSockets, receive messages from windows and the browser, use IndexedDB, and post messages to other windows.