Process RTCP Packets in OnTrack examples

TWCC and Receiver Reports are needed for a good default experience

examples/save-to-disk/main.go

@@ -116,6 +116,18 @@ func main() {
 			}
 		}()
 
+		// Read incoming RTCP packets
+		// Before these packets are returned they are processed by interceptors. For things
+		// like TWCC and RTCP Reports this needs to be called.
+		go func() {
+			rtcpBuf := make([]byte, 1500)
+			for {
+				if _, _, rtcpErr := receiver.Read(rtcpBuf); rtcpErr != nil {
+					return
+				}
+			}
+		}()
+
 		codec := track.Codec()
 		if strings.EqualFold(codec.MimeType, webrtc.MimeTypeOpus) {
 			fmt.Println("Got Opus track, saving to disk as output.opus (48 kHz, 2 channels)")