Intercepting HTTP Response headers with Angular 4.3's HttpInterceptor

This is how I send my HTTP request:

return this.http.get(url, { observe: 'response' })

I would like to read the HTTP headers of a HttpResponse in my HttpInterceptor:

intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        return next.handle(request)
            .do(event => {
                if (event instanceof HttpResponse) {
                    this.logger.logDebug(event); // Headers are missing here
                }
            })
            .catch((err: HttpErrorResponse) => {
            // Do stuff
    }
}

The interceptor is provided like this in my app.module.ts:

{ provide: HTTP_INTERCEPTORS, useClass: MyHttpInterceptor, multi: true }

The event seems to have no headers, and even in the Chrome Dev Console I cannot see any headers:

However, when using Postman, I can see the headers in the response (as expected)

Connection →keep-alive
Content-Length →14766
Content-Type →application/json
Date →Fri, 04 Aug 2017 14:50:46 GMT
Server →WildFly/10
X-Powered-By →Undertow/1

How can I reveal these headers in Angular ?

The official docs for HTTP says to get the headers like this:

http
  .get<MyJsonData>('/data.json', {observe: 'response'})
  .subscribe(resp => {
    // Here, resp is of type HttpResponse<MyJsonData>.
    // You can inspect its headers:
    console.log(resp.headers.get('X-Custom-Header'));
    // And access the body directly, which is typed as MyJsonData as requested.
    console.log(resp.body.someField);
  });