Add comment clarifying the purpose of Scheduler

Author: ljwagerfield

src/private/Scheduler.ts

@@ -1,5 +1,13 @@
 import { ConsoleUtils } from "./ConsoleUtils";
 
+/**
+ * -------------------------
+ * Q: Why not use 'setTimeout'?
+ * -------------------------
+ * A: setTimeout can be paused (e.g., during hibernation), risking JWT expiration before it triggers.
+ *    We therefore use a scheduler to check wall-clock time every second and execute the callback at the scheduled time.
+ * -------------------------
+ */
 export class Scheduler {
   private callbacks: { [handle: number]: { callback: () => void; epoch: number } } = {};
   private nextId: number = 0;

src/public/browser/AuthManagerBrowser.ts

@@ -148,6 +148,8 @@ class AuthManagerImpl implements AuthManagerInterface {
         // Use 'warn' instead of 'error' since this happens frequently, i.e. user goes through a tunnel, and some customers report these errors to systems like Sentry, so we don't want to spam.
         ConsoleUtils.warn(`Unable to refresh JWT access token: ${e as string}`);
       } finally {
+        // 'setTimeout' can be paused (e.g., during hibernation), risking JWT expiration before it triggers. We use a
+        // scheduler to check wall-clock time every second and execute the callback at the scheduled time (below).
         session.accessTokenRefreshHandle = this.scheduler.schedule(expires, () => {
           this.refreshAccessToken(session).then(
             () => {},