code: public static <T> Position.Writable<T> writable(final Type type, Consumer<T> consumer) {
          return new W<>(Validate.notNull(type, "type"), Validate.notNull(consumer, "consumer"));
      }
docs: Get a writable position of type {@code type}. No checking can be done to ensure that {@code type} conforms to
  {@code T}.
  
  @param type not {@code null}
  @param consumer not {@code null}
  @return Position.Writable