code: private DefaultProxyRoutePlanner createProxyRoutePlanner(HttpSettings settings, HttpAsyncClientBuilder httpClientBuilder) {
          HttpHost proxy = new HttpHost(settings.getProxyUrl().getHost(), settings.getProxyUrl().getPort());
          if (settings.getProxyUser() != null) {
              CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
              String proxyUser = settings.getProxyUser();
              String proxyPassword = settings.getProxyPassword();
              UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(proxyUser, proxyPassword);
              credentialsProvider.setCredentials(new AuthScope(proxy), credentials);
              httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
          }
          return new DefaultProxyRoutePlanner(proxy);
      }
docs: Creates default proxy route planner.
  
  @param settings
  settings to use.
  @param httpClientBuilder
  http client builder.
  @return Instance of {@link DefaultProxyRoutePlanner}.