public PriorityChannelSpec priority(String id) {
   return MessageChannels.priority(id);
 }
 public QueueChannelSpec.MessageStoreSpec priority(
     PriorityCapableChannelMessageStore messageGroupStore, Object groupId) {
   return MessageChannels.priority(messageGroupStore, groupId);
 }
 public PriorityChannelSpec priority() {
   return MessageChannels.priority();
 }