diff --git a/app_client.py b/app_client.py
index e1c25c8..1a7ed28 100644
--- a/app_client.py
+++ b/app_client.py
@@ -3,6 +3,12 @@
 Created on Sun Mar 22 10:46:20 2020
 
 @author: cpan
+
+This client example is for non-blocking demonstation. It is going to hang if
+the server does not send response due to some reasons. E.g. connection dropped.
+While multi-connection non-blocking is essential for server, it is not
+necessary the best choice for the client.
+
 """
 
 import sys