@Override
    public void close(final CloseMode closeMode) {
        this.connManager.close(closeMode);
    }
Minimal implementation of {@link CloseableHttpClient}. This client is
optimized for HTTP/1.1 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 4.3
httpclient5/src/main/java/org/apache/hc/client5/http/impl/classic/MinimalHttpClient.java