I am having hard time understanding this. Any src where it is explained ? "Each consumer process belongs to a consumer group and each message is delivered to exactly one process within every consumer group. Hence a consumer group allows many processes or machines to logically act as a single consumer. The concept of consumer group is very powerful and can be used to support the semantics of either a queue or topic as found in JMS. To support queue semantics, we can put all consumers in a single consumer group, in which case each message will go to a single consumer. To support topic semantics, each consumer is put in its own consumer group, and then all consumers will receive each message. A more common case in our own usage is that we have multiple logical consumer groups, each consisting of a cluster of consuming machines that act as a logical whole. Kafka has the added benefit in the case of large data that no matter how many consumers a topic has, a message is stored only a single time."
/Samal
