code: void expireAfterWrite(String key, @Nullable String value) {
      requireArgument(expireAfterWriteDuration == UNSET_INT, "expireAfterWrite was already set");
      expireAfterWriteDuration = parseDuration(key, value);
      expireAfterWriteTimeUnit = parseTimeUnit(key, value);
    }
docs: Configures expire after write.