Merge pull request #575 from CrOrc/CrOrc-fix-resolve-IE-11

Co-authored-by: NJake Champion <me@jakechampion.name>

fetch.js

@@ -471,19 +471,27 @@ export function fetch(input, init) {
       }
       options.url = 'responseURL' in xhr ? xhr.responseURL : options.headers.get('X-Request-URL')
       var body = 'response' in xhr ? xhr.response : xhr.responseText
+      setTimeout(function() {
         resolve(new Response(body, options))
+      }, 0)
     }
 
     xhr.onerror = function() {
+      setTimeout(function() {
         reject(new TypeError('Network request failed'))
+      }, 0)
     }
 
     xhr.ontimeout = function() {
+      setTimeout(function() {
         reject(new TypeError('Network request failed'))
+      }, 0)
     }
 
     xhr.onabort = function() {
+      setTimeout(function() {
         reject(new DOMException('Aborted', 'AbortError'))
+      }, 0)
     }
 
     function fixUrl(url) {