Which event should I subscribe to control header value? about boomerang

[andreas-marschke]

If you look at the code here: https://github.com/akamai/boomerang/blob/master/plugins/auto-xhr.js#L2232
You can find the xhr_init function that's called when an XHR is being initialized(open(ed)).

Unfortunately, as you can see when you scroll down to around here: https://github.com/akamai/boomerang/blob/master/plugins/auto-xhr.js#L2365
You'll see there's no chance for you to modify any and all network requests made on the page to include a header value.

However, if you intend to add that feature, feel free to contribute it to the team :)