Unhandled promise rejection: RTCEngine's onMediaSectionsRequirement handler calls negotiate() without a catch #2134

Describe the bug

In RTCEngine.setupSignalClientCallbacks(), the onMediaSectionsRequirement handler fires off negotiate() without handling its promise:

this.client.onMediaSectionsRequirement = requirement => {
  this.addMediaSections(requirement.numAudios, requirement.numVideos);
  this.negotiate();            // <- returned promise is never caught
};

negotiate() rejects with a NegotiationError in normal operating conditions, e.g. negotiation timed out on a poor network, or PC manager is closed during teardown. Here that rejection becomes an unhandled promise rejection.

Every other internal caller already catches it:

this.negotiate().catch(err => { this.log.error(err); });

negotiate() already starts the disconnect/reconnect flow on failure, so only the stray promise is the problem. In React Native it surfaces as a global onunhandledrejection, which crash reporters show as an error with no app frames. We saw it in production as NegotiationError: negotiation timed out from users on weak Wi-Fi.

Reproduction

Node 20+, against the published ESM bundle:

let unhandled = 0;
process.on('unhandledRejection', (e) => { unhandled++; console.log('unhandled:', e?.name, e?.message); });
const lk = await import('livekit-client/dist/livekit-client.esm.mjs');
const engine = new lk.Room().engine;
engine.setupSignalClientCallbacks();
engine.addMediaSections = () => {};
engine.pcManager = undefined;                 // negotiate() rejects: NegotiationError('PC manager is closed')
engine.client.onMediaSectionsRequirement({ numAudios: 1, numVideos: 0 });
await new Promise((r) => setTimeout(r, 200));
console.log('unhandled rejections =', unhandled); // 1

With a .catch() on that call, the count is 0.

Expected behavior

The rejection is caught and logged, like the other negotiate() call sites.

Suggested fix

 this.client.onMediaSectionsRequirement = requirement => {
   this.addMediaSections(requirement.numAudios, requirement.numVideos);
-  this.negotiate();
+  this.negotiate().catch(err => {
+    this.log.warn('negotiation for new media sections failed', { ...this.logContext, error: err });
+  });
 };

Environment

• livekit-client 2.22.3 (latest); also present in 2.20.1
• React Native 0.83 (Hermes) with @livekit/react-native
• Possibly related: Coalesce burst negotiations and avoid full-reconnect on single NegotiationError under concurrent signaling #1915 (negotiation bursts and NegotiationError under concurrent signaling)