agent/tcs/handler/handler.go
func heartbeatHandler(timer *time.Timer) func(*ecstcs.HeartbeatMessage) {
	return func(*ecstcs.HeartbeatMessage) {
		seelog.Debug("Received HeartbeatMessage from tcs")
		timer.Reset(retry.AddJitter(defaultHeartbeatTimeout, defaultHeartbeatJitter))
	}
}
func heartbeatHandler(timer *time.Timer) func(*ecstcs.HeartbeatMessage) {
	return func(*ecstcs.HeartbeatMessage) {
		seelog.Debug("Received HeartbeatMessage from tcs")
		timer.Reset(retry.AddJitter(defaultHeartbeatTimeout, defaultHeartbeatJitter))
	}
}
// heartbeatHandler resets the heartbeat timer when HeartbeatMessage message is received from tcs.