Performance: Use a shared timer for polling RTP stats

This is now only relevant in case the user has enabled the developer option to show advanced media statistics, but still an easy performance fix.

src/state/media/observeRtpStreamStats.ts

@@ -19,10 +19,15 @@ import {
   startWith,
   switchMap,
   map,
+  share,
 } from "rxjs";
 
 import { observeTrackReference$ } from "../observeTrackReference";
 
+// Use a shared timer for all the stats observers so that we don't clog up the
+// event loop with hundreds of timers in large calls
+const refreshStats$ = interval(1000).pipe(share());
+
 export function observeRtpStreamStats$(
   participant: Participant,
   source: Track.Source,
@@ -32,7 +37,7 @@ export function observeRtpStreamStats$(
 > {
   return combineLatest([
     observeTrackReference$(participant, source),
-    interval(1000).pipe(startWith(0)),
+    refreshStats$.pipe(startWith(0)),
   ]).pipe(
     switchMap(async ([trackReference]) => {
       const track = trackReference?.publication?.track;