[Bug] SampleAsyncProducer causes core dump

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar-client-cpp/issues) and found nothing similar.

### Version

pulsar cpp client 3.5.1

### Minimal reproduce step

run the example: SampleAsyncProducer.cc

### What did you expect to see?

it will produce the messages

### What did you see instead?

it will have the coredump

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!