From a mailing list post, we learned we can adjust the priority of network requests in Necko. Methinks it makes sense to lower the priority of FHR's network traffic since it's a background service. From the post: Code for setting it looks like this: priorityChannel->AdjustPriority(nsISupportsPriority::PRIORITY_LOWEST); where priorityChannel is an instance of nsISupportsPriority.

FHR is going away per bug 1209088, wontfix.