* cache.
     *
     * @param project The project that employs the plugin realm, must not be {@code null}.
     * @param record The cache record being used for the project, must not be {@code null}.
     */
    void register(MavenProject project, Key key, CacheRecord record);

        return CacheUtils.pluginHashCode(plugin);
    }

    protected static boolean pluginEquals(Plugin a, Plugin b) {
        return CacheUtils.pluginEquals(a, b);
    }

    public void register(MavenProject project, Key cacheKey, CacheRecord record) {
        // default cache does not track record usage
    }

        }
    }

    @Override
    public void flush() {
        cache.clear();
    }

    @Override
    public void register(MavenProject project, Key cacheKey, CacheRecord record) {
        // default cache does not track record usage
    }

@Experimental
@Consumer
public interface ExtensibleEnumProvider<T extends ExtensibleEnum> extends SpiService {

    /**
     * Registers new values for the T extensible enum.
     *
     * @return a collection of T instances to register
     */
    @Nonnull
    Collection<T> provides();

     * cache.
     *
     * @param project The project that employs the plugin realm, must not be {@code null}.
     * @param record The cache record being used for the project, must not be {@code null}.
     */
    void register(MavenProject project, Key cacheKey, CacheRecord record);

     * cache.
     *
     * @param project The project that employs the plugin realm, must not be {@code null}.
     * @param record The cache record being used for the project, must not be {@code null}.
     */
    void register(MavenProject project, Key cacheKey, CacheRecord record);

     * cache.
     *
     * @param project The project that employs the plugin realm, must not be {@code null}.
     * @param record The cache record being used for the project, must not be {@code null}.
     */
    void register(MavenProject project, Key key, CacheRecord record);

     * cache.
     *
     * @param project The project that employs the plugin realm, must not be {@code null}.
     * @param record The cache record being used for the project, must not be {@code null}.
     */
    void register(MavenProject project, Key key, CacheRecord record);