[client] Fix ICE latency handling (#4501)

The GetSelectedCandidatePair() does not carry the latency information.

Author: pappz

client/internal/peer/worker_ice.go

@@ -218,7 +218,9 @@ func (w *WorkerICE) reCreateAgent(dialerCancel context.CancelFunc, candidates []
 		return nil, err
 	}
 
-	if err := agent.OnSelectedCandidatePairChange(w.onICESelectedCandidatePair); err != nil {
+	if err := agent.OnSelectedCandidatePairChange(func(c1, c2 ice.Candidate) {
+		w.onICESelectedCandidatePair(agent, c1, c2)
+	}); err != nil {
 		return nil, err
 	}
 
@@ -365,26 +367,17 @@ func (w *WorkerICE) onICECandidate(candidate ice.Candidate) {
 	}()
 }
 
-func (w *WorkerICE) onICESelectedCandidatePair(c1 ice.Candidate, c2 ice.Candidate) {
+func (w *WorkerICE) onICESelectedCandidatePair(agent *icemaker.ThreadSafeAgent, c1, c2 ice.Candidate) {
 	w.log.Debugf("selected candidate pair [local <-> remote] -> [%s <-> %s], peer %s", c1.String(), c2.String(),
 		w.config.Key)
 
-	w.muxAgent.Lock()
-
-	pair, err := w.agent.GetSelectedCandidatePair()
-	if err != nil {
-		w.log.Warnf("failed to get selected candidate pair: %s", err)
-		w.muxAgent.Unlock()
-		return
-	}
-	if pair == nil {
-		w.log.Warnf("selected candidate pair is nil, cannot proceed")
-		w.muxAgent.Unlock()
+	pairStat, ok := agent.GetSelectedCandidatePairStats()
+	if !ok {
+		w.log.Warnf("failed to get selected candidate pair stats")
 		return
 	}
-	w.muxAgent.Unlock()
 
-	duration := time.Duration(pair.CurrentRoundTripTime() * float64(time.Second))
+	duration := time.Duration(pairStat.CurrentRoundTripTime * float64(time.Second))
 	if err := w.statusRecorder.UpdateLatency(w.config.Key, duration); err != nil {
 		w.log.Debugf("failed to update latency for peer: %s", err)
 		return