title: How to retrieve exact reason of the error from async HttpRequest?
body: <p>I am trying to figure out how to find out exact reason of (async) HttpRequest (from 'dart:html') failure, and, to be honest, I am a bit lost here.</p>
  
  <p>The onError callback receives only HttpRequestProgressError object, which doesn't have anything useful, and the HttpRequest object itself has "status" set to "0" in case of failure, even console shows "Failed to load resource" with no details.</p>
  
  <p>What I want is to know the exact reason - like "connection refused" or "host name not resolved".</p>
  
  <p>Is this possible at all?</p>
  
  <p>Thank you!</p>