do not delete topic from msgRouter after unsubscribe

Author: sanket28

client.go

@@ -639,9 +639,9 @@ func (c *client) Unsubscribe(topics ...string) Token {
 	copy(unsub.Topics, topics)
 
 	c.oboundP <- &PacketAndToken{p: unsub, t: token}
-	for _, topic := range topics {
-		c.msgRouter.deleteRoute(topic)
-	}
+	// for _, topic := range topics {
+	// 	c.msgRouter.deleteRoute(topic)
+	// }
 
 	DEBUG.Println(CLI, "exit Unsubscribe")
 	return token