code: public static <S> State<S, Unit> put(S s) {
          return new State<>(constantly(tuple(UNIT, s)));
      }
docs: Create a {@link State} that ignores its initial state, returning a {@link Unit} result and <code>s</code> as its
  final state.
  
  @param s   the final state
  @param <S> the state type
  @return the new {@link State} instance