handle nil MessageChannel

pkg/routing/redisrouter.go

@@ -407,6 +407,9 @@ func (r *RedisRouter) handleRTCMessage(rm *livekit.RTCNodeMessage) error {
 		r.lock.RLock()
 		requestChan := r.requestChannels[pKey]
 		r.lock.RUnlock()
+		if requestChan == nil {
+			return ErrChannelClosed
+		}
 		if err := requestChan.WriteMessage(rmb.Request); err != nil {
 			return err
 		}

pkg/rtc/participant.go

@@ -748,6 +748,9 @@ func (p *ParticipantImpl) writeMessage(msg *livekit.SignalResponse) error {
 		return nil
 	}
 	sink := p.params.Sink
+	if sink == nil {
+		return nil
+	}
 	err := sink.WriteMessage(msg)
 	if err != nil {
 		logger.Warnw("could not send message to participant", err,