public <T extends OUT> PulsarSourceBuilder<T> setDeserializationSchema(
            PulsarDeserializationSchema<T> deserializationSchema) {
        PulsarSourceBuilder<T> self = specialized();
        self.deserializationSchema = deserializationSchema;
        return self;
    }
PulsarDeserializationSchema is required for deserializing messages from Pulsar and getting
the {@link TypeInformation} for message serialization in flink.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/pulsar/src/main/java/org/apache/inlong/sort/pulsar/source/PulsarSourceBuilder.java