[Feature] 修改terminate session 功能

coco/session.py

@@ -79,6 +79,11 @@ class Session:
         self.sel.unregister(sharer)
         self._sharers.remove(sharer)
 
+    def terminate(self):
+        msg = b"Terminate by administrator\r\n"
+        self.client.send(msg)
+        self.close()
+
     def bridge(self):
         """
         Bridge clients with server

coco/tasks.py

@@ -24,7 +24,7 @@ class TaskHandler:
                 break
 
         if session:
-            session.close()
+            session.terminate()
         self.app.service.finish_task(task.id)
 
     def handle(self, task):