code: public static void withLink(Representation representation, String rel, String href, Predicate<ReadableRepresentation> predicate) {
          withLink(representation, rel, href,
                   Optional.of(predicate),
                   Optional.<String>absent(),
                   Optional.<String>absent(),
                   Optional.<String>absent(),
                   Optional.<String>absent());
      }
docs: Add a link to this resource
  
  @param rel
  @param href The target href for the link, relative to the href of this resource.