refine the default smi

@@ -876,7 +876,7 @@ vhost stream.control.com {
     # @remark 0 to disable the minimal interval.
     # @remark >0 to make the srs to send message one by one.
     # default: 0
-    send_min_interval   3;
+    send_min_interval   10;
 }
 
 # the vhost for antisuck.