docs: public void mergeLinks(HalResource<?> embedded) {
      for (Entry<HalRelation, Set<String>> linkentry : embedded.linker.linkedResources.entrySet()) {
        Set<String> linkedIdSet = linkedResources.get(linkentry.getKey());
        if(linkedIdSet != null) {
          linkedIdSet.addAll(linkentry.getValue());
        }else {
          linkedResources.put(linkentry.getKey(), linkentry.getValue());
        }
      }
    }