This allows people to add routes which consumes from JMS destinations, by which the consumer should start async in a separate thread, this ensures Camel will continue starting the route, and continue the code. Then the asyns thread starts the JmsConsumer in the background. This is needed in case the remote connection to the JMS broker does not work. But you want to signal the route is started anyway, as the JMS consumer most likely support failover and retry, so the connection may come online later.
We may need to add some way to store a flag, so you from JMX can monitor if the JMS consumer is live or not.