How do I get an edge boot error message from Windows.Web.Http.Diagnostics?

I am making a program to receive http events from Edge tabs using the UWP windows.web.http.diagnostics api . I reached to get http events from Edge. For example, when an HTTP request is sent (navigate to another page in a browser), I receive a requestSent event . So far, so good.

Now I want to get loading error but I don't know how to get it in Edge and what kind of messages I should get from the http.diagnostics API.

Can anyone give me some hint on how to generate boot error messages in Edge and what I get from the windows.web.http.diagnostics api?

Thank!

Edit (11-Aug-2017):

After some investigation it seems that in the current version of the windows.web.http.diagnostics API, this information is not provided by events. So this is not possible.