Here, we must commit the offsets right after receiving a batch from a call to .poll()

doc represents optional description of message

Protocol buffers isn't a natively supported type for the Confluent REST Proxy, but you may use the binary format instead

Once the client connects to any broker, it is connected to the entire cluster and in case of leadership changes, the clients automatically do a Metadata Request to an available broker to find out who is the new leader for the topic. Hence the producer will automatically keep on producing to the correct Kafka Broker

The Controller is a broker that is responsible for electing partition leaders