DebeziumEngine RecordChangeEvents cannot be modified

class MyEngine {

    private DebeziumEngine engine;

    // [...] denotes omitted irrelevant portions

    public void run(final DebeziumMysqlSourceConnectorConfiguration configuration,
                    final Environment environment) {

        engine = DebeziumEngine
                .create(ChangeEventFormat.of(Connect.class))
                .using(new Properties())
                .notifying(new MyChangeConsumer())
                .build();

        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(engine);
    }

    class MyChangeConsumer implements DebeziumEngine.ChangeConsumer<RecordChangeEvent<SourceRecord>> {
        @Override
        public void handleBatch(List<RecordChangeEvent<SourceRecord>> records,
                                DebeziumEngine.RecordCommitter<RecordChangeEvent<SourceRecord>> committer)
                throws InterruptedException {
            SourceRecord lastRecord = null;
            for (RecordChangeEvent<SourceRecord> recordChangeEvent : records) {
                SourceRecord record = recordChangeEvent.record();
                try {
                    // [...] process the record, but don't commit it
                } catch (StopConnectorException | StopEngineException ex) {
                    // [...] handle exception
                } catch (Exception e) {
                    // [...] handle exception
                }
                lastRecord = record;
            }

            // [...] block until all messages are published to kafka

            // create new record offset info
            Map<String, String> newSourceOffset = (Map<String, String>) lastRecord.sourceOffset();
            Map<String, Long> topicToKakfaOffsetMap = new HashMap<>();
            // get the latest offset published to kafka
            topicToKakfaOffsetMap.put("topic_partition1", 1L);
            newSourceOffset.put("topicOffsetMap", new JSONObject(topicToKakfaOffsetMap).toString());


            // Create a new source record that contains the offsets for each partition
            // This is used to skip messages upon recovery to preserve exactly once semantics
            SourceRecord mergedRecord = new SourceRecord(lastRecord.sourcePartition(), newSourceOffset, lastRecord.topic(),
                    lastRecord.kafkaPartition(), lastRecord.keySchema(), lastRecord.key(), lastRecord.valueSchema(), lastRecord.value(),
                    lastRecord.timestamp(), lastRecord.headers());

            // Create a new record change
            // to contain the merged record with offset data
            RecordChangeEvent<SourceRecord> mergedRecordChangeEvent = new RecordChangeEvent<SourceRecord>() {
                @Override
                public SourceRecord record() {
                    return mergedRecord;
                }
            };
            // Next line throws a cast error at runtime because we cannot
            // Cast from a RecordChangeEvent to an EmbeddedChangeEvent
            committer.markProcessed(mergedRecordChangeEvent);
            committer.markBatchFinished();
        }
    }
}

ERROR [2021-01-05 19:42:10,635] io.debezium.embedded.EmbeddedEngine: Stopping connector after error in the application's handler method: class com.yelp.MysqlConnector.DebeziumMysqlSourceConnectorApplication$MyChangeConsumer$1 cannot be cast to class io.debezium.embedded.EmbeddedEngineChangeEvent
[…]
! at io.debezium.embedded.ConvertingEngineBuilder$1.markProcessed(ConvertingEngineBuilder.java:89)