How to get active fetch ajax requests count?

How to get active fetch ajax requests count?

When a site is using jquery/XMLhttp  requests  we were able to get  active   ajax  calls in the backend using jQuery.active. But when a site is using aurelia  fetch  for  ajax  calls, how to get number of  active   fetch  calls in the backend? tried by injecting some javascript code too get calls but not able to get active fetch requests being processed
(function() {
    var oldOpen = XMLHttpRequest.prototype.open;
    window.openHTTPs = 0;
    XMLHttpRequest.prototype.open = function(method, url, async, user, pass) {
      window.openHTTPs++;
      this.addEventListener("readystatechange", function() {
          if(this.readyState == 4) {
            window.openHTTPs--;
          }
        }, false);
      oldOpen.call(this, method, url, async, user, pass);
    }
  })(XMLHttpRequest);