code: public static CodecRegistry codecRegistryFromGson(final Gson gson) {
      Preconditions.checkNotNull(gson, "gson");
      return new CodecRegistry() {
        @Override
        public <T> Codec<T> get(Class<T> clazz) {
          return codecFromTypeAdapter(clazz, gson.getAdapter(clazz));
        }
      };
    }
docs: Given existing {@code Gson} instance builds a {@link CodecRegistry}.
  
  @param gson preconfigured instance
  @return wrapper for {@code gson}.