code: public static <K,V> ExtendedMutableConfiguration<K,V> of(Cache2kBuilder<K,V> builder) {
      return of(builder.toConfiguration());
    }
docs: The preferred way to construct a JCache based on a cache2k configuration.
  It is not needed to set any original parameters from {@link MutableConfiguration}.
  It is possible to set parameters defined by JCache, e.g.
  {@link MutableConfiguration#setCacheLoaderFactory(Factory)}. In this case the
  settings will be merged. See the documentation.
  
  @see <a href="https://cache2k.org/docs/latest/user-guide.html#jcache">User Guide - JCache</a>