public <T extends OUT> PulsarSourceBuilder<T> setDeserializationSchema(
            PulsarDeserializationSchema<T> deserializationSchema) {
        PulsarSourceBuilder<T> self = specialized();
        self.deserializationSchema = deserializationSchema;
        return self;
    }
DeserializationSchema is required for getting the {@link Schema} for deserialize message from
pulsar and getting the {@link TypeInformation} for message serialization in flink.

<p>We have defined a set of implementations, using {@code
PulsarDeserializationSchema#pulsarSchema} or {@code PulsarDeserializationSchema#flinkSchema}
for creating the desired schema.
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/pulsar/src/main/java/org/apache/inlong/sort/pulsar/source/PulsarSourceBuilder.java