title: In Angular4 HttpClient.get , none of the custom headers returned back
body: <p>My backend is spring boot 1.5.7 and the front end is angular4.4.3,</p>
  
  <p>the response dont include all headers actually it includes only cache-control,content-type ,pragma and expires 
  while the custom headers not there and the same time postman show that all others are returned </p>
  
  <pre><code>constructor(private http2: HttpClient) { }   
  listAll{ this.http2.get&lt;ItemsResponse&gt;('http://mysite:8080' , {observe: 'response'}).subscribe(resp =&gt; {
  console.log(resp.headers.get('xyz'));
  console.log(resp.body.response);
  }
  );
  </code></pre>