consume

public function consume(int $timeoutMs): Message {}

Consume message(s) (will also get error events and triggers callbacks)
Registered callbacks will be automaically called rebalanceCallback, logCallback, etc.
On error $message->err will not be RD_KAFKA_ERR_NO_ERROR but contain the acutal error code.

$conf = SimpleKafkaClient\Configuration();
$conf->set('metadata.broker.list', 'kafka:9092');
$consumer = new SimpleKafkaClient\Consumer($conf);
$message = $consumer->consume(20000);

An application should call consume() at regular intervals, even if no messages
are expected, to serve any queued callbacks waiting to be called.