Implement AsyncStream to listen for remote config updates

FirebaseRemoteConfig/Swift/RemoteConfig+AsyncStream.swift

@@ -0,0 +1,32 @@
+// Copyright 2025 Google LLC
+//
+// 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.
+
+public extension RemoteConfig {
+  /// Asynchronous stream of configuration updates.
+  @available(iOS 13.0, macOS 10.15, macCatalyst 13.0, watchOS 7.0, tvOS 13.0, *)
+  var updateStream: AsyncStream<Result<RemoteConfigUpdate, Error>> {
+    AsyncStream { continuation in
+      let registration = self.addOnConfigUpdateListener { update, error in
+        if let error = error {
+          continuation.yield(.failure(error))
+        } else if let update {
+          continuation.yield(.success(update))
+        }
+      }
+      continuation.onTermination = { _ in
+        registration.remove()
+      }
+    }
+  }
+}

FirebaseRemoteConfig/Tests/Swift/SwiftAPI/APITests.swift

@@ -179,6 +179,31 @@
     registration.remove()
   }
 
+  func testRealtimeRemoteConfigRealConsoleAsync() async {
+    guard APITests.useFakeConfig == false else { return }
+
+    let expectation = expectation(description: #function)
+
+    let task = Task {
+      for await updateResult in config.updateStream {
+        switch updateResult {
+        case let .success(update):
+          XCTAssertNotNil(update)
+          XCTAssertNotNil(update.updatedKeys.contains(Constants.jedi))
+        case let .failure(error):
+          XCTFail("Expected a successful update result, but received an error: \(error)")
+        }
+
+        expectation.fulfill()
+      }
+    }
+
+    console.updateRemoteConfigValue(Constants.yoda, forKey: Constants.jedi)
+
+    await fulfillment(of: [expectation], timeout: 5.0)
+    task.cancel()
+  }
+
   // MARK: - RemoteConfigConsole Tests
 
   func testFetchConfigThenUpdateConsoleThenFetchAgain() {
@@ -268,7 +293,7 @@
 
   private func waitForExpectations() {
     let kTestTimeout = 10.0
     waitForExpectations(timeout: kTestTimeout,
                         handler: { error in
                           if let error {
                             print(error)