feat(webrtc): add Connected() channel to Peer for ICE establishment timing

core/webrtc/peer.go

@@ -63,8 +63,10 @@ type Peer struct {
 	videoSub    chan *rtp.Packet
 	audioSub    chan *rtp.Packet
 
-	done chan struct{}
-	once sync.Once
+	done      chan struct{}
+	once      sync.Once
+	connected chan struct{}
+	connOnce  sync.Once
 }
 
 // CreatePeer builds a PeerConnection, sets the remote offer, generates an
@@ -131,9 +133,13 @@ func (f *PeerFactory) CreatePeer(ctx context.Context, src *Source, offer webrtc.
 		source:     src,
 		sub:        sub,
 		done:       make(chan struct{}),
+		connected:  make(chan struct{}),
 	}
 
 	pc.OnConnectionStateChange(func(st webrtc.PeerConnectionState) {
+		if st == webrtc.PeerConnectionStateConnected {
+			p.connOnce.Do(func() { close(p.connected) })
+		}
 		if st == webrtc.PeerConnectionStateFailed ||
 			st == webrtc.PeerConnectionStateDisconnected ||
 			st == webrtc.PeerConnectionStateClosed {
@@ -158,6 +164,12 @@ func (p *Peer) ResourceID() string { return p.resourceID }
 // index cleanup without polling.
 func (p *Peer) Done() <-chan struct{} { return p.done }
 
+// Connected returns a channel that is closed the first time Pion reports
+// PeerConnectionStateConnected. Callers that need to measure ICE
+// establishment duration select on Connected() vs Done() from the moment
+// the peer is created.
+func (p *Peer) Connected() <-chan struct{} { return p.connected }
+
 // Close tears down the peer connection and unsubscribes from each
 // source. Safe to call multiple times.
 func (p *Peer) Close() error {
@@ -248,9 +260,13 @@ func (f *PeerFactory) CreatePeerFromSources(ctx context.Context,
 		videoSub:    videoSub,
 		audioSub:    audioSub,
 		done:        make(chan struct{}),
+		connected:   make(chan struct{}),
 	}
 
 	pc.OnConnectionStateChange(func(st webrtc.PeerConnectionState) {
+		if st == webrtc.PeerConnectionStateConnected {
+			p.connOnce.Do(func() { close(p.connected) })
+		}
 		if st == webrtc.PeerConnectionStateFailed ||
 			st == webrtc.PeerConnectionStateDisconnected ||
 			st == webrtc.PeerConnectionStateClosed {
@@ -263,7 +279,6 @@ func (f *PeerFactory) CreatePeerFromSources(ctx context.Context,
 	return p, nil
 }
 
-
 // AddICECandidate forwards a trickle-ICE candidate to the underlying
 // PeerConnection. Returns the underlying error if the candidate is
 // malformed or the connection has already been closed.