KerberosRestTemplate does not scale well

I want to create a KerberosRestTemplate extension with userPrincipal, password, and loginOptions parameters. I also want to configure the timeout. Currently, this requires copying classes and methods, as they are private static. This means that you have to copy the entire class code

But I want it to be

import java.util.Map;

import org.apache.hc.client5.http.config.ConnectionConfig;
import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager;
import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
import org.apache.hc.core5.util.Timeout;
import org.springframework.security.kerberos.client.KerberosRestTemplate;

public class CustomKerberosRestTemplate extends KerberosRestTemplate {
    public CustomKerberosRestTemplate(
            String userPrincipal,
            String password,
            Map<String, Object> loginOptions
    ) {
        super(null, userPrincipal, password, loginOptions);
    }

    @Override
    protected void customizeHttpClient(HttpClientBuilder builder) {
        PoolingHttpClientConnectionManager connectionManager = PoolingHttpClientConnectionManagerBuilder.create()
                .setDefaultConnectionConfig(ConnectionConfig.custom()
                        .setSocketTimeout(Timeout.ofSeconds(10))
                        .setConnectTimeout(Timeout.ofSeconds(10))
                        .build())
                .build();
        builder.setConnectionManager(connectionManager);
    }
}

Start by locating KerberosRestTemplate and reviewing the private static methods that currently force users to copy the class. Define an extension point for customizing the HttpClientBuilder and support the requested constructor parameters and timeout configuration. Done means a subclass can provide these options without copying the implementation, with coverage for the new behavior.