@Override
                        public void failed(final Exception ex) {
                            System.out.println(request + "->" + ex);
                        }
This example demonstrates how to make HttpClient negotiate or force a particular
version of HTTP protocol during the TLS handshake.
<p/>
Please note that protocol version policy setting also applies to non-HTTPS
connections.
httpclient5/src/test/java/org/apache/hc/client5/http/examples/AsyncClientHttpVersionPolicy.java