From e3bf82625e1572e54dee0f3225512de61f5f2d08 Mon Sep 17 00:00:00 2001
From: David Heinemeier Hansson <david@loudthinking.com>
Date: Tue, 7 Jul 2015 22:33:48 +0200
Subject: [PATCH] Document heartbeat purpose

---
 lib/action_cable/connection/heartbeat.rb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/action_cable/connection/heartbeat.rb b/lib/action_cable/connection/heartbeat.rb
index 47cd937c25..e0f4a97f53 100644
--- a/lib/action_cable/connection/heartbeat.rb
+++ b/lib/action_cable/connection/heartbeat.rb
@@ -1,5 +1,8 @@
 module ActionCable
   module Connection
+    # Websocket connection implementations differ on when they'll mark a connection as stale. We basically never want a connection to go stale, as you
+    # then can't rely on being able to receive and send to it. So there's a 3 second heartbeat running on all connections. If the beat fails, we automatically
+    # disconnect.
     class Heartbeat
       BEAT_INTERVAL = 3