private void doCommitAsync(Map<TopicPartition, OffsetAndMetadata> offsets, final int seqno) {
        log.debug("{} Committing offsets asynchronously using sequence number {}: {}", this, seqno, offsets);
        OffsetCommitCallback cb = (tpOffsets, error) -> onCommitCompleted(error, seqno, tpOffsets);
        consumer.commitAsync(offsets, cb);
    }
Poll for new messages with the given timeout. Should only be invoked by the worker thread.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerSinkTask.java