Update examples to handle going to Closed

Relates to #1767

examples/custom-logger/main.go

@@ -100,6 +100,12 @@ func main() {
 			fmt.Println("Peer Connection has gone to failed exiting")
 			os.Exit(0)
 		}
+
+		if s == webrtc.PeerConnectionStateClosed {
+			// PeerConnection was explicitly closed. This usually happens from a DTLS CloseNotify
+			fmt.Println("Peer Connection has gone to closed exiting")
+			os.Exit(0)
+		}
 	})
 
 	// Set the handler for Peer connection state