@Override
  public boolean equals(final Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null || getClass() != obj.getClass()) {
      return false;
    }
    final ErrorPayload that = (ErrorPayload) obj;
    return Objects.equals(this.errorMessage, that.errorMessage)
        && Objects.equals(this.critical, that.critical);
  }
Indicates whether the error is critical.
iotdb-client/service-rpc/src/main/java/org/apache/iotdb/rpc/subscription/payload/poll/ErrorPayload.java