code: public static <T> Key<T> of(Class<T> type,
                                Class<? extends Annotation> annType)
    {
      Objects.requireNonNull(type);
      Objects.requireNonNull(annType);
  
      return new Key<>(type, new Class[] { annType });
    }
docs: Builds Key from Class and annotation type
  
  @param type    target type
  @param annType associated annotation
  @param <T>     type
  @return instance of a Key