Clarify usecase is comments

Author: abhinavsingh

README.md

@@ -2685,6 +2685,13 @@ options:
                         events.
   --inactive-conn-cleanup-timeout INACTIVE_CONN_CLEANUP_TIMEOUT
                         Time after which inactive works must be cleaned up.
+                        Increase this value if your backend services are slow
+                        to response or when proxy.py is handling a high
+                        volume. When running proxy.py on Google Cloud (GCP)
+                        you may see 'backend_connection_closed_before_data_sen
+                        t_to_client', with curl clients you may see 'Empty
+                        reply from server' error when '--inactive-conn-
+                        cleanup-timeout' value is low for your use-case.
                         Default 1 seconds
   --enable-proxy-protocol
                         Default: False. If used, will enable proxy protocol.

proxy/core/work/threadless.py

@@ -41,7 +41,12 @@
 proxy_flags.add_argument(
     "--inactive-conn-cleanup-timeout",
     default=DEFAULT_INACTIVE_CONN_CLEANUP_TIMEOUT,
-    help="Time after which inactive works must be cleaned up. Default {0} seconds".format(
+    help="Time after which inactive works must be cleaned up. "
+    + "Increase this value if your backend services are slow to response "
+    + "or when proxy.py is handling a high volume. When running proxy.py on Google Cloud (GCP) "
+    + "you may see 'backend_connection_closed_before_data_sent_to_client', with curl clients "
+    + "you may see 'Empty reply from server' error when '--inactive-conn-cleanup-timeout' "
+    + "value is low for your use-case. Default {0} seconds".format(
         DEFAULT_INACTIVE_CONN_CLEANUP_TIMEOUT
     ),
 )