@Internal
    @Override
    public SourceReader<OUT, PulsarPartitionSplit> createReader(SourceReaderContext readerContext)
            throws Exception {
        return PulsarSourceReader.create(
                sourceConfiguration, deserializationSchema, pulsarCrypto, readerContext);
    }
Get a PulsarSourceBuilder to builder a {@link PulsarSource}.

@return a Pulsar source builder.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/pulsar/src/main/java/org/apache/inlong/sort/pulsar/source/PulsarSource.java