spring cloud stream - RabbitmQ - 并发消费者

Question

使用带有RabbitMQ的Spring云流。我正在尝试让消费者同时使用消息。下面的属性已设置，但它无法正常工作。我缺少任何必需的属性（使用版本Brooklyn.SR3）？

spring.cloud.stream.rabbit.bindings.channel.consumer.acknowledgementMOde = None
spring.cloud.stream.rabbit.bindings.channel.consumer.prefetch = 50
spring.cloud.stream.bindings.channel.consumer.concurrency =50
spring.cloud.stream.rabbit.bindings.channel.consumer.maxConcurrency = 50