protected Map<String, String> coreReportMessage() {
    final Map<String, String> result = new HashMap<>();
    final CachedSubscriptionPollResponse currentResponse = getCurrentResponse();
    result.put(
        "currentResponse",
        Objects.nonNull(currentResponse) ? currentResponse.toString() : "<unknown>");
    result.put("hasNoMore", String.valueOf(hasNoMore));
    return result;
  }
The {@code SubscriptionEventExtendableResponse} class represents a subscription event response
that can dynamically change as new responses are fetched. It maintains a list of {@link
CachedSubscriptionPollResponse} objects and provides methods for managing and serializing these
responses.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/subscription/event/response/SubscriptionEventExtendableResponse.java