@Experimental
    public static Executor newInstance(final CloseableHttpAsyncClient httpclient) {
        return new Executor(httpclient != null ? new ClassicToAsyncAdaptor(httpclient, Timeout.ofMinutes(5)) : GET_ASYNC_CLIENT());
    }
This feature is considered experimental and may be discontinued in the future.
@since 5.5
httpclient5-fluent/src/main/java/org/apache/hc/client5/http/fluent/Executor.java