@Test
    public void testSerializeRecordToJsonExpandingValue() throws Exception {
        SchemaType schemaType = SchemaType.AVRO;
        RecordSchemaBuilder valueSchemaBuilder = org.apache.pulsar.client.api.schema.SchemaBuilder.record("value");
        valueSchemaBuilder.field("a").type(SchemaType.BYTES).optional().defaultValue(null);
        GenericSchema<GenericRecord> valueSchema = Schema.generic(valueSchemaBuilder.build(schemaType));

        GenericRecord valueGenericRecord = valueSchema.newRecordBuilder()
                .set("a", "10".getBytes(StandardCharsets.UTF_8))
                .build();

        Record<GenericObject> genericObjectRecord = new Record<>() {

            @Override
            public org.apache.pulsar.client.api.Schema getSchema() {
                return valueSchema;
            }

            @Override
            public GenericObject getValue() {
                return valueGenericRecord;
            }
        };

        ObjectMapper objectMapper = new ObjectMapper().setSerializationInclusion(JsonInclude.Include.NON_NULL);
        String json = Utils.serializeRecordToJsonExpandingValue(objectMapper, genericObjectRecord, true);

        assertEquals(json, "{\"payload.a\":\"MTA=\"}");
    }