REQ-2481: 支持动态调整优先级

im-center-server/src/main/java/cn/axzo/im/job/SendMessageJob.java

@@ -52,6 +52,7 @@ public class SendMessageJob extends IJobHandler {
         SendManager sendManager = sendExec.getSendManager();
         if (sendManager != null) {
             sendManager.interrupt();
+            // 这个要放到同步快里面, 避免在上次任务没有结果前就执行下次任务, 导致重复发送
             sendManager.awaitTasksTermination();
         }
         this.sendExec = null;