ReactiveCocoa
diff --git a/‎Examples/CaseStudies/CaseStudies.xcodeproj/project.pbxproj
+4 b/‎Examples/CaseStudies/CaseStudies.xcodeproj/project.pbxproj
+4
diff --git a/‎Examples/CaseStudies/SwiftUICaseStudies/00-Core.swift
+21-17 b/‎Examples/CaseStudies/SwiftUICaseStudies/00-Core.swift
+21-17
diff --git a/‎Examples/CaseStudies/SwiftUICaseStudies/01-GettingStarted-Animations.swift
+8-25 b/‎Examples/CaseStudies/SwiftUICaseStudies/01-GettingStarted-Animations.swift
+8-25
diff --git a/‎Examples/CaseStudies/SwiftUICaseStudies/02-Effects-Basics.swift
+23-5 b/‎Examples/CaseStudies/SwiftUICaseStudies/02-Effects-Basics.swift
+23-5
diff --git a/‎Examples/CaseStudies/SwiftUICaseStudies/02-Effects-Cancellation.swift
+30-32 b/‎Examples/CaseStudies/SwiftUICaseStudies/02-Effects-Cancellation.swift
+30-32
@@ -930,6 +930,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
+				OTHER_SWIFT_FLAGS = "-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks";
 				PRODUCT_BUNDLE_IDENTIFIER = co.pointfree.UIKitCaseStudies;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_VERSION = 5.0;
@@ -949,6 +950,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
+				OTHER_SWIFT_FLAGS = "-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks";
 				PRODUCT_BUNDLE_IDENTIFIER = co.pointfree.UIKitCaseStudies;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_VERSION = 5.0;
@@ -1121,6 +1123,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
+				OTHER_SWIFT_FLAGS = "-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks";
 				PRODUCT_BUNDLE_IDENTIFIER = co.pointfree.SwiftUICaseStudies;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_VERSION = 5.0;
@@ -1139,6 +1142,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
+				OTHER_SWIFT_FLAGS = "-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks";
 				PRODUCT_BUNDLE_IDENTIFIER = co.pointfree.SwiftUICaseStudies;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_VERSION = 5.0;
 
@@ -66,25 +66,31 @@ enum RootAction {
 }
 
 struct RootEnvironment {
-  var date: () -> Date
+  var date: @Sendable () -> Date
   var downloadClient: DownloadClient
   var fact: FactClient
-  var favorite: (UUID, Bool) -> Effect<Bool, Error>
-  var fetchNumber: () -> Effect<Int, Never>
+  var favorite: @Sendable (UUID, Bool) async throws -> Bool
+  var fetchNumber: @Sendable () async throws -> Int
   var mainQueue: DateScheduler
-  var notificationCenter: NotificationCenter
-  var uuid: () -> UUID
+  var screenshots: @Sendable () async -> AsyncStream<Void>
+  var uuid: @Sendable () -> UUID
   var webSocket: WebSocketClient
 
   static let live = Self(
-    date: Date.init,
+    date: { Date() },
     downloadClient: .live,
     fact: .live,
     favorite: favorite(id:isFavorite:),
     fetchNumber: liveFetchNumber,
     mainQueue: QueueScheduler.main,
-    notificationCenter: .default,
-    uuid: UUID.init,
+    screenshots: { @MainActor in
+      AsyncStream(
+        NotificationCenter.default
+          .notifications(named: UIApplication.userDidTakeScreenshotNotification)
+          .map { _ in }
+      )
+    },
+    uuid: { UUID() },
     webSocket: .live
   )
 }
@@ -146,13 +152,13 @@ let rootReducer = Reducer<RootState, RootAction, RootEnvironment>.combine(
     .pullback(
       state: \.effectsCancellation,
       action: /RootAction.effectsCancellation,
-      environment: { .init(fact: $0.fact, mainQueue: $0.mainQueue) }
+      environment: { .init(fact: $0.fact) }
     ),
   episodesReducer
     .pullback(
       state: \.episodes,
       action: /RootAction.episodes,
-      environment: { .init(favorite: $0.favorite, mainQueue: $0.mainQueue) }
+      environment: { .init(favorite: $0.favorite) }
     ),
   focusDemoReducer
     .pullback(
@@ -188,7 +194,7 @@ let rootReducer = Reducer<RootState, RootAction, RootEnvironment>.combine(
     .pullback(
       state: \.longLivingEffects,
       action: /RootAction.longLivingEffects,
-      environment: { .init(notificationCenter: $0.notificationCenter) }
+      environment: { .init(screenshots: $0.screenshots) }
     ),
   mapAppReducer
     .pullback(
@@ -243,9 +249,7 @@ let rootReducer = Reducer<RootState, RootAction, RootEnvironment>.combine(
     .pullback(
       state: \.refreshable,
       action: /RootAction.refreshable,
-      environment: {
-        .init(fact: $0.fact, mainQueue: $0.mainQueue)
-      }
+      environment: { .init(fact: $0.fact, mainQueue: $0.mainQueue) }
     ),
   sharedStateReducer
     .pullback(
@@ -275,7 +279,7 @@ let rootReducer = Reducer<RootState, RootAction, RootEnvironment>.combine(
 .debug()
 .signpost()
 
-private func liveFetchNumber() -> Effect<Int, Never> {
-  Effect.deferred { Effect(value: Int.random(in: 1...1_000)) }
-    .delay(1, on: QueueScheduler.main)
+@Sendable private func liveFetchNumber() async throws -> Int {
+  try await Task.sleep(nanoseconds: NSEC_PER_SEC)
+  return Int.random(in: 1...1_000)
 }
@@ -1,6 +1,6 @@
 import ComposableArchitecture
 import ReactiveSwift
-import SwiftUI
+@preconcurrency import SwiftUI  // NB: SwiftUI.Color and SwiftUI.Animation are not Sendable yet.
 
 private let readMe = """
   This screen demonstrates how changes to application state can drive animations. Because the \
@@ -19,32 +19,14 @@ private let readMe = """
   toggle at the bottom of the screen.
   """
 
-extension Effect where Error == Never {
-  public static func keyFrames(
-    values: [(output: Value, duration: TimeInterval)],
-    scheduler: DateScheduler
-  ) -> Self {
-    .concatenate(
-      values
-        .enumerated()
-        .map { index, animationState in
-          index == 0
-            ? Effect(value: animationState.output)
-            : Effect(value: animationState.output)
-              .delay(values[index - 1].duration, on: scheduler)
-        }
-    )
-  }
-}
-
 struct AnimationsState: Equatable {
   var alert: AlertState<AnimationsAction>?
   var circleCenter: CGPoint?
   var circleColor = Color.black
   var isCircleScaled = false
 }
 
-enum AnimationsAction: Equatable {
+enum AnimationsAction: Equatable, Sendable {
   case alertDismissed
   case circleScaleToggleChanged(Bool)
   case rainbowButtonTapped
@@ -72,11 +54,12 @@ let animationsReducer = Reducer<AnimationsState, AnimationsAction, AnimationsEnv
     return .none
 
   case .rainbowButtonTapped:
-    return .keyFrames(
-      values: [Color.red, .blue, .green, .orange, .pink, .purple, .yellow, .black]
-        .map { (output: .setColor($0), duration: 1) },
-      scheduler: environment.mainQueue.animation(.linear)
-    )
+    return .run { send in
+      for color in [Color.red, .blue, .green, .orange, .pink, .purple, .yellow, .black] {
+        await send(.setColor(color), animation: .linear)
+        try await environment.mainQueue.sleep(for: .seconds(1))
+      }
+    }
     .cancellable(id: CancelID.self)
 
   case .resetButtonTapped:
 
@@ -30,9 +30,10 @@ struct EffectsBasicsState: Equatable {
 
 enum EffectsBasicsAction: Equatable {
   case decrementButtonTapped
+  case decrementDelayResponse
   case incrementButtonTapped
   case numberFactButtonTapped
-  case numberFactResponse(Result<String, FactClient.Failure>)
+  case numberFactResponse(TaskResult<String>)
 }
 
 struct EffectsBasicsEnvironment {
@@ -47,25 +48,42 @@ let effectsBasicsReducer = Reducer<
   EffectsBasicsAction,
   EffectsBasicsEnvironment
 > { state, action, environment in
+  enum DelayID {}
+
   switch action {
   case .decrementButtonTapped:
     state.count -= 1
     state.numberFact = nil
+    // Return an effect that re-increments the count after 1 second if the count is negative
+    return state.count >= 0
+      ? .none
+      : .task {
+        try await environment.mainQueue.sleep(for: .seconds(1))
+        return .decrementDelayResponse
+      }
+      .cancellable(id: DelayID.self)
+
+  case .decrementDelayResponse:
+    if state.count < 0 {
+      state.count += 1
+    }
     return .none
 
   case .incrementButtonTapped:
     state.count += 1
     state.numberFact = nil
-    return .none
+    return state.count >= 0
+      ? .cancel(id: DelayID.self)
+      : .none
 
   case .numberFactButtonTapped:
     state.isNumberFactRequestInFlight = true
     state.numberFact = nil
     // Return an effect that fetches a number fact from the API and returns the
     // value back to the reducer's `numberFactResponse` action.
-    return environment.fact.fetch(state.count)
-      .observe(on: environment.mainQueue)
-      .catchToEffect(EffectsBasicsAction.numberFactResponse)
+    return .task { [count = state.count] in
+      await .numberFactResponse(TaskResult { try await environment.fact.fetch(count) })
+    }
 
   case let .numberFactResponse(.success(response)):
     state.isNumberFactRequestInFlight = false
 
@@ -18,20 +18,19 @@ private let readMe = """
 
 struct EffectsCancellationState: Equatable {
   var count = 0
-  var currentTrivia: String?
-  var isTriviaRequestInFlight = false
+  var currentFact: String?
+  var isFactRequestInFlight = false
 }
 
 enum EffectsCancellationAction: Equatable {
   case cancelButtonTapped
   case stepperChanged(Int)
-  case triviaButtonTapped
-  case triviaResponse(Result<String, FactClient.Failure>)
+  case factButtonTapped
+  case factResponse(TaskResult<String>)
 }
 
 struct EffectsCancellationEnvironment {
   var fact: FactClient
-  var mainQueue: DateScheduler
 }
 
 // MARK: - Business logic
@@ -40,35 +39,35 @@ let effectsCancellationReducer = Reducer<
   EffectsCancellationState, EffectsCancellationAction, EffectsCancellationEnvironment
 > { state, action, environment in
 
-  enum TriviaRequestId {}
+  enum NumberFactRequestID {}
 
   switch action {
   case .cancelButtonTapped:
-    state.isTriviaRequestInFlight = false
-    return .cancel(id: TriviaRequestId.self)
+    state.isFactRequestInFlight = false
+    return .cancel(id: NumberFactRequestID.self)
 
   case let .stepperChanged(value):
     state.count = value
-    state.currentTrivia = nil
-    state.isTriviaRequestInFlight = false
-    return .cancel(id: TriviaRequestId.self)
-
-  case .triviaButtonTapped:
-    state.currentTrivia = nil
-    state.isTriviaRequestInFlight = true
-
-    return environment.fact.fetch(state.count)
-      .observe(on: environment.mainQueue)
-      .catchToEffect(EffectsCancellationAction.triviaResponse)
-      .cancellable(id: TriviaRequestId.self)
-
-  case let .triviaResponse(.success(response)):
-    state.isTriviaRequestInFlight = false
-    state.currentTrivia = response
+    state.currentFact = nil
+    state.isFactRequestInFlight = false
+    return .cancel(id: NumberFactRequestID.self)
+
+  case .factButtonTapped:
+    state.currentFact = nil
+    state.isFactRequestInFlight = true
+
+    return .task { [count = state.count] in
+      await .factResponse(TaskResult { try await environment.fact.fetch(count) })
+    }
+    .cancellable(id: NumberFactRequestID.self)
+
+  case let .factResponse(.success(response)):
+    state.isFactRequestInFlight = false
+    state.currentFact = response
     return .none
 
-  case .triviaResponse(.failure):
-    state.isTriviaRequestInFlight = false
+  case .factResponse(.failure):
+    state.isFactRequestInFlight = false
     return .none
   }
 }
@@ -91,7 +90,7 @@ struct EffectsCancellationView: View {
             value: viewStore.binding(get: \.count, send: EffectsCancellationAction.stepperChanged)
           )
 
-          if viewStore.isTriviaRequestInFlight {
+          if viewStore.isFactRequestInFlight {
             HStack {
               Button("Cancel") { viewStore.send(.cancelButtonTapped) }
               Spacer()
@@ -101,11 +100,11 @@ struct EffectsCancellationView: View {
                 .id(UUID())
             }
           } else {
-            Button("Number fact") { viewStore.send(.triviaButtonTapped) }
-              .disabled(viewStore.isTriviaRequestInFlight)
+            Button("Number fact") { viewStore.send(.factButtonTapped) }
+              .disabled(viewStore.isFactRequestInFlight)
           }
 
-          viewStore.currentTrivia.map {
+          viewStore.currentFact.map {
             Text($0).padding(.vertical, 8)
           }
         }
@@ -134,8 +133,7 @@ struct EffectsCancellation_Previews: PreviewProvider {
           initialState: EffectsCancellationState(),
           reducer: effectsCancellationReducer,
           environment: EffectsCancellationEnvironment(
-            fact: .live,
-            mainQueue: QueueScheduler.main
+            fact: .live
           )
         )
       )