@Override
    public InputStatus pollNext(ReaderOutput<OUT> output) throws Exception {
        checkErrorAndRethrow();
        return super.pollNext(output);
    }
The map to store the start time of each checkpoint.
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/pulsar/src/main/java/org/apache/inlong/sort/pulsar/source/reader/PulsarOrderedSourceReader.java