Receive a message from the consumer.
Receive a message from the consumer. Receives compete for messages, each message is returned by exactly one receive.
Receive messages continuously and call the provided callback function for each message.
Receive messages continuously and call the provided callback function for each message. If there are multiple subscriptions, they will compete for messages and each message will be delivered to exactly one callback function.
(Since version ) see corresponding Javadoc for more information.
The usual semantics of a consumer is that each message is delivered to exactly one receive or subscription. Therefore, multiple subscriptions on a consumer receive messages randomly. If messages need to be delivered multiple times, each receiver should have a separate consumer.