Voice Broadcast playback (#9372)

* Implement actual voice broadcast playback

* Move PublicInterface type to test

* Implement pausing a voice broadcast playback

* Implement PR feedback

* Remove unnecessary early return

src/events/getReferenceRelationsForEvent.ts

@@ -0,0 +1,33 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { EventType, MatrixClient, MatrixEvent, RelationType } from "matrix-js-sdk/src/matrix";
+import { Relations } from "matrix-js-sdk/src/models/relations";
+
+import { VoiceBroadcastInfoEventType } from "../voice-broadcast";
+
+export const getReferenceRelationsForEvent = (
+    event: MatrixEvent,
+    messageType: EventType | typeof VoiceBroadcastInfoEventType,
+    client: MatrixClient,
+): Relations | undefined => {
+    const room = client.getRoom(event.getRoomId());
+    return room?.getUnfilteredTimelineSet()?.relations?.getChildEventsForEvent(
+        event.getId(),
+        RelationType.Reference,
+        messageType,
+    );
+};

src/events/index.ts

@@ -16,3 +16,4 @@ limitations under the License.
 
 export { getForwardableEvent } from './forward/getForwardableEvent';
 export { getShareableLocationEvent } from './location/getShareableLocationEvent';
+export * from "./getReferenceRelationsForEvent";