@Override
                    public void completed(final AsyncConnectionEndpoint result) {
                        future.completed(new InternalAsyncClientEndpoint(result));
                    }
Minimal implementation of {@link CloseableHttpAsyncClient}. This client is
optimized for HTTP/1.1 and HTTP/2 message transport and does not support
advanced HTTP protocol functionality such as request execution via a proxy,
state management, authentication and request redirects.
<p>
Concurrent message exchanges executed by this client will get assigned to
separate connections leased from the connection pool.
</p>

@since 5.0
httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/MinimalHttpAsyncClient.java