private static WorkerTransactionContext buildTransactionContext(SourceConnectorConfig sourceConfig) {
        return TransactionBoundary.CONNECTOR.equals(sourceConfig.transactionBoundary())
                ? new WorkerTransactionContext()
                : null;
    }
WorkerTask that uses a {@link SourceTask} to ingest data into Kafka, with support for exactly-once semantics.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/ExactlyOnceWorkerSourceTask.java