in flink-connector-rabbitmq/src/main/java/org/apache/flink/streaming/connectors/rabbitmq/RMQSource.java [395:399]
public void setFallBackIdentifiers(String correlationId, long deliveryTag) {
this.correlationId = correlationId;
this.deliveryTag = deliveryTag;
this.customIdentifiersSet = false;
}