xForwardedFor: []string{"8.8.8.8"},
			xRealIP:       []string{"1.1.1.1"},
		},
	}
	// When X-Forwarded-For and X-Real-IP headers are both present, X-Forwarded-For takes precedence.
	res := GetSourceIP(req)
	if res != "8.8.8.8" {
		t.Errorf("wrong header, xff takes precedence: got %s, want: 8.8.8.8", res)
	}

	// When explicitly disabled, the XFF header is ignored and X-Real-IP is used.
	enableXFFHeader = false
	defer func() {

                context, context.invokerRequest.coreExtensions().orElseThrow());
    }

    /**
     * Selects extensions to load discovered from various sources by precedence ("first wins"), as
     * {@link InvokerRequest#coreExtensions()} is in precedence order. Also reports conflicts, if any.
     * Finally, at DEBUG level reports configured vs selected extensions.
     */

     * {@link CoreExtensions} is validated, but the list elements may have overlapping elements, that requires
     * some logic to sort out (like precedence).
     * <p>
     * The list of {@link CoreExtensions} if present, is in precedence order.
     *
     * @return an {@link Optional} containing the {@link CoreExtensions}, or empty if not configured
     */
    @Nonnull

    File getGlobalSettingsFile();

    /**
     * Sets the global settings file. A non-existent settings file is equivalent to empty settings. If both user
     * settings and global settings are given, the user settings take precedence.
     *
     * @param globalSettingsFile The global settings file, may be {@code null} to disable global settings.
     * @return This request, never {@code null}.
     */

     */
    Source getGlobalToolchainsSource();

    /**
     * Sets the global toolchains source. If both user toolchains and a global toolchains are given, the user toolchains
     * take precedence.
     *
     * @param globalToolchainsSource The global toolchains source, may be {@code null} to disable global toolchains.
     * @return This request, never {@code null}.
     */

        assertThrows(InvokerException.class, () -> invoke(cwd, userHome, List.of("validate"), List.of()));
    }

    /**
     * In case of conflict spanning different sources, precedence is applied: project > user > installation.
     */
    @Test
    void conflictingExtensionsFromDifferentSource(
            @TempDir(cleanup = CleanupMode.ON_SUCCESS) Path cwd,

     */
    enum RepositoryMerging {

        /**
         * The repositories declared in the POM have precedence over the repositories specified in the request.
         */
        POM_DOMINANT,

        /**
         * The repositories specified in the request have precedence over the repositories declared in the POM.
         */
        REQUEST_DOMINANT,
    }

     */
    enum RepositoryMerging {

        /**
         * The repositories declared in the POM have precedence over the repositories specified in the request.
         */
        POM_DOMINANT,

        /**
         * The repositories specified in the request have precedence over the repositories declared in the POM.
         */
        REQUEST_DOMINANT,
    }

    @Nonnull

     * defined precedence onto each other to achieve proper precedence. Precedence is defined as:
     * <ul>
     *     <li>System properties (lowest precedence)</li>
     *     <li>Project properties (optional)</li>
     *     <li>User properties (highest precedence)</li>
     * </ul>

import java.util.function.Consumer;
import java.util.function.Function;

import org.apache.maven.api.cli.Options;
import org.apache.maven.api.cli.ParserRequest;

/**
 * Options that are "layered" by precedence order.
 *
 * @param <O> The type of options.
 */
public abstract class LayeredOptions<O extends Options> implements Options {
    protected final List<O> options;

    protected LayeredOptions(List<O> options) {