Which observer is fired at t=0 in har?

Question

I am making extension for firefox and wondering which observer listens on the event at time=0 in har file.

Here are some homework I did: I found that http-on-modify-request will be fired for all requests from firefox. However, if I listen on the first http-on-modify-request event, I got this event triggered even before the firefox GUI is loaded, and also as I compared its time with its har file, the timing is off.

Answer 1

Without knowing what exactly Firebug is doing, I suspect that it is using progress listeners. So the "event" being recorded is an onStateChange call with STATE_START and STATE_IS_WINDOW flags - a load was started in a particular browser tab.