code: public static <T extends Case1<A>, A, EA extends A> DecomposableMatchBuilder0<T> case1(
        Class<T> clazz, DecomposableMatchBuilder0<EA> a) {
      List<Matcher<Object>> matchers = Lists.of(ArgumentMatchers.any());
      return new DecomposableMatchBuilder1<T, EA>(matchers, 0, new Case1FieldExtractor<>(clazz))
          .decomposeFirst(a);
    }
docs: Matches a case class of one element.
  
  <p>If matched, the {@code a} value is decomposed to 0.