How to use the @aurelia/runtime-html.DOM.createCustomEvent function in @aurelia/runtime-html

private trackRequestStart(): void {
    this.isRequesting = !!(++this.activeRequestCount);
    if (this.isRequesting) {
      const evt = DOM.createCustomEvent('aurelia-fetch-client-request-started', { bubbles: true, cancelable: true });
      DOM.window.setTimeout(() => { DOM.dispatchEvent(evt); }, 1);
    }
  }

private trackRequestEnd(): void {
    this.isRequesting = !!(--this.activeRequestCount);
    if (!this.isRequesting) {
      const evt = DOM.createCustomEvent('aurelia-fetch-client-requests-drained', { bubbles: true, cancelable: true });
      DOM.window.setTimeout(() => { DOM.dispatchEvent(evt); }, 1);
    }
  }

trackRequestEnd() {
        this.isRequesting = !!(--this.activeRequestCount);
        if (!this.isRequesting) {
            const evt = DOM.createCustomEvent('aurelia-fetch-client-requests-drained', { bubbles: true, cancelable: true });
            DOM.window.setTimeout(() => { DOM.dispatchEvent(evt); }, 1);
        }
    }
    processRequest(request, interceptors) {

trackRequestStart() {
        this.isRequesting = !!(++this.activeRequestCount);
        if (this.isRequesting) {
            const evt = DOM.createCustomEvent('aurelia-fetch-client-request-started', { bubbles: true, cancelable: true });
            DOM.window.setTimeout(() => { DOM.dispatchEvent(evt); }, 1);
        }
    }
    trackRequestEnd() {