public SourceExactlyMetric getSourceExactlyMetric() {
        return sourceExactlyMetric;
    }
getter for PulsarSourceReader to record metrics
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/pulsar/src/main/java/org/apache/inlong/sort/pulsar/table/PulsarTableDeserializationSchema.java