Segfault while closing the consumer while consume loop is running

[milindl]

Reproduction code:

function runConsumer() {
    const consumer = new RdKafka.KafkaConsumer({
        'group.id': 'test-group' + Math.random(),
        'bootstrap.servers': 'localhost:9092',
    }, {
        'auto.offset.reset': 'earliest',
    });

    consumer.connect();

    consumer.on('ready', () => {
        console.log("Consumer is ready");
        consumer.subscribe(['test-topic']);
        consumer.consume(); // consume loop
    });

    consumer.on('data', (data) => {
        console.log("Received data");
        console.log(data);
        consumer.disconnect();
    });

    consumer.on('event.error', (err) => {
        console.error(err);
    });
}

Cause: NodeKafka::Workers::KafkaConsumerConsumeLoop::HandleMessageCallback is called after KafkaConsumerConsumerLoop:Close and the callback has been cleared by that time so callback->Call causes a segfault.