Add voice broadcast state event (#6785)

Riot/Modules/VoiceBroadcast/VoiceBroadcastSDK/VoiceBroadcastServiceError.swift

@@ -0,0 +1,38 @@
+// 
+// Copyright 2022 New Vector Ltd
+//
+// 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 Foundation
+
+/// VoiceBroadcastService error
+public enum VoiceBroadcastServiceError: Int, Error {
+    case missingUserId
+    case roomNotFound
+    case notStarted
+    case unknown
+}
+
+// MARK: - VoiceBroadcastService errors
+extension VoiceBroadcastServiceError: CustomNSError {
+    public static let errorDomain = "io.element.voice_broadcast_info"
+
+    public var errorCode: Int {
+        return Int(rawValue)
+    }
+
+    public var errorUserInfo: [String: Any] {
+        return [:]
+    }
+}