public ApiException error() {
        return error;
    }
Returns `ApiException` if the log directory is offline or an error occurred, otherwise returns null.
<ul>
<li> KafkaStorageException - The log directory is offline.
<li> UnknownServerException - The server experienced an unexpected error when processing the request.
</ul>
clients/src/main/java/org/apache/kafka/clients/admin/LogDirDescription.java