为什么simplejmsListenerContainerFactory不提供并发配置?

在上设置并发 @JmsListener 注释:

/**
 * The concurrency limits for the listener, if any. Overrides the value defined
 * by the container factory used to create the listener container.
 * <p>The concurrency limits can be a "lower-upper" String &mdash; for example,
 * "5-10" &mdash; or a simple upper limit String &mdash; for example, "10", in
 * which case the lower limit will be 1.
 * <p>Note that the underlying container may or may not support all features.
 * For instance, it may not be able to scale, in which case only the upper limit
 * is used.
 */
String concurrency() default "";

不过,看起来javadocs是错的

Overrides the value defined
 * by the container factory used to create the listener container.