This is a stop gap example how we can obtain the delay id

src/state/CallViewModel/CallViewModel.ts

@@ -100,6 +100,7 @@ import { createHomeserverConnected$ } from "./localMember/HomeserverConnected.ts
 import {
   createLocalMembership$,
   enterRTCSession,
+  MatrixState,
   RTCBackendState,
 } from "./localMember/LocalMembership.ts";
 import { createLocalTransport$ } from "./localMember/LocalTransport.ts";

src/state/CallViewModel/localMember/LocalMembership.ts

@@ -580,6 +580,21 @@ export const createLocalMembership$ = ({
     };
   }
 
+  matrixState$.pipe(scope.bind()).subscribe((matrixState) => {
+    if (matrixState.state !== MatrixState.Connected) return;
+
+    // UNSAVE. Arbitrary change some types to read properties we should not have access to (private)
+    // TODO this is bad and we need a proper solution to expose the delayId (or let the js-sdk take care of delegating the delayed event)
+    const sessionWithAccessToPrivateMembers = matrixRTCSession as unknown as {
+      membershipManager: { state: { delayId: string } };
+    };
+    const delayId =
+      sessionWithAccessToPrivateMembers.membershipManager.state.delayId;
+    logger.debug("delayId is available", delayId);
+    // call
+    void passDelayIdToJWT(delayId);
+  });
+
   return {
     startTracks,
     requestConnect,
@@ -673,3 +688,14 @@ export async function enterRTCSession(
     await widget.api.transport.send(ElementWidgetActions.JoinCall, {});
   }
 }
+
+async function passDelayIdToJWT(delayId: string): Promise<void> {
+  // CHANGE ME!
+  // try{
+  //   await fetch(sth using delayId)
+  // }catch(error){
+  //   // at a minimum log the error (maybe we can do sth smarter)
+  //   logger.error(error);
+  // }
+  return Promise.resolve();
+}