nsIIOService2 in Firefox 2.0

 While this is set, IOService will monitor an nsINetworkLinkService
 (if available) and set its offline status to "true" whenever
 isLinkUp is false.

 Applications that want to control changes to the IOService's offline
 status should set this to false, watch for network:link-status-changed
 broadcasts, and change nsIIOService::offline as they see fit. Note
 that this means during application startup, IOService may be offline
 if there is no link, until application code runs and can turn off
 this management.