code: public static <T> GinMultibinder<T> newSetBinder(GinBinder binder, TypeLiteral<T> type) {
      return newSetBinder(binder, type, Key.get(providerOf(type)));
    }
docs: Returns a new multibinder that collects instances of {@code type} in a {@link java.util.Set}
  that is itself bound with no binding annotation.