diff --git a/Samples/SwiftUITestbed/Sources/AppDelegate.swift b/Samples/SwiftUITestbed/Sources/AppDelegate.swift
index 38c48e2df..89204be39 100644
--- a/Samples/SwiftUITestbed/Sources/AppDelegate.swift
+++ b/Samples/SwiftUITestbed/Sources/AppDelegate.swift
@@ -25,7 +25,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         window = UIWindow(frame: UIScreen.main.bounds)
         window?.rootViewController = WorkflowHostingController(
-            workflow: RootWorkflow(close: nil)
+            workflow: RootWorkflow()
                 .mapRendering(MarketRootScreen.init)
                 .mapRendering(ModalHostContainer.init)
         )
diff --git a/Samples/SwiftUITestbed/Sources/MainScreen.swift b/Samples/SwiftUITestbed/Sources/MainScreen.swift
index 2ea124462..5f97c988b 100644
--- a/Samples/SwiftUITestbed/Sources/MainScreen.swift
+++ b/Samples/SwiftUITestbed/Sources/MainScreen.swift
@@ -19,7 +19,7 @@ import MarketUI
 import MarketWorkflowUI
 import ViewEnvironment
 
-struct MainScreen: MarketScreen {
+struct MainScreen: MarketScreen, Equatable {
     enum Field: Hashable {
         case title
     }
@@ -27,16 +27,11 @@ struct MainScreen: MarketScreen {
     @FocusState var focusedField: Field?
 
     let title: String
-    let didChangeTitle: (String) -> Void
-
+    let canClose: Bool
     let allCapsToggleIsOn: Bool
     let allCapsToggleIsEnabled: Bool
-    let didChangeAllCapsToggle: (Bool) -> Void
-
-    let didTapPushScreen: () -> Void
-    let didTapPresentScreen: () -> Void
 
-    let didTapClose: (() -> Void)?
+    let sink: StableSink<Action>
 
     func element(
         in context: MarketWorkflowUI.MarketScreenContext,
@@ -56,7 +51,7 @@ struct MainScreen: MarketScreen {
                     style: styles.fields.textField,
                     label: "Text",
                     text: title,
-                    onChange: didChangeTitle,
+                    onChange: { sink.send(.changeTitle($0)) },
                     onReturn: { _ in focusedField = nil }
                 )
                 .focused(when: $focusedField, equals: .title)
@@ -77,7 +72,7 @@ struct MainScreen: MarketScreen {
                         isOn: allCapsToggleIsOn,
                         isEnabled: allCapsToggleIsEnabled,
                         accessibilityLabel: "is all caps",
-                        onChange: didChangeAllCapsToggle
+                        onChange: { sink.send(.changeAllCaps($0)) }
                     )
                 }
 
@@ -91,13 +86,13 @@ struct MainScreen: MarketScreen {
                 MarketButton(
                     style: styles.button(rank: .secondary),
                     text: "Push Screen",
-                    onTap: didTapPushScreen
+                    onTap: sink.closure(.pushScreen)
                 )
 
                 MarketButton(
                     style: styles.button(rank: .secondary),
                     text: "Present Screen",
-                    onTap: didTapPresentScreen
+                    onTap: sink.closure(.presentScreen)
                 )
             }
         }
@@ -108,9 +103,26 @@ extension MainScreen: MarketBackStackContentScreen {
     func backStackItem(in environment: ViewEnvironment) -> MarketUI.MarketNavigationItem {
         MarketNavigationItem(
             title: .text(.init(regular: title)),
-            backButton: didTapClose.map { .close(onTap: $0) } ?? .automatic()
+            backButton: canClose ? .close(onTap: sink.closure(.close)) : .automatic()
         )
     }
 
     var backStackIdentifier: AnyHashable? { nil }
 }
+
+extension MainScreen {
+    enum Action {
+        case pushScreen
+        case presentScreen
+        case changeTitle(String)
+        case changeAllCaps(Bool)
+        case close
+    }
+}
+
+// I guess this could be upstreamed to Blueprint
+extension FocusState: Equatable where Value: Equatable {
+    public static func == (lhs: FocusState<Value>, rhs: FocusState<Value>) -> Bool {
+        lhs.wrappedValue == rhs.wrappedValue
+    }
+}
diff --git a/Samples/SwiftUITestbed/Sources/MainWorkflow.swift b/Samples/SwiftUITestbed/Sources/MainWorkflow.swift
index d8b0e5ae0..7e04640a4 100644
--- a/Samples/SwiftUITestbed/Sources/MainWorkflow.swift
+++ b/Samples/SwiftUITestbed/Sources/MainWorkflow.swift
@@ -18,16 +18,18 @@ import MarketWorkflowUI
 import Workflow
 
 struct MainWorkflow: Workflow {
-    let didClose: (() -> Void)?
+    let canClose: Bool
 
     enum Output {
         case pushScreen
         case presentScreen
+        case close
     }
 
     struct State {
         var title: String
         var isAllCaps: Bool
+        let trampoline = SinkTrampoline()
 
         init(title: String) {
             self.title = title
@@ -39,49 +41,44 @@ struct MainWorkflow: Workflow {
         State(title: "New item")
     }
 
-    enum Action: WorkflowAction {
-        typealias WorkflowType = MainWorkflow
-
-        case pushScreen
-        case presentScreen
-        case changeTitle(String)
-        case changeAllCaps(Bool)
-
-        func apply(toState state: inout WorkflowType.State) -> WorkflowType.Output? {
-            switch self {
-            case .pushScreen:
-                return .pushScreen
-            case .presentScreen:
-                return .presentScreen
-            case .changeTitle(let newValue):
-                state.title = newValue
-                state.isAllCaps = newValue.isAllCaps
-            case .changeAllCaps(let isAllCaps):
-                state.isAllCaps = isAllCaps
-                state.title = isAllCaps ? state.title.uppercased() : state.title.lowercased()
-            }
-            return nil
-        }
-    }
-
     typealias Rendering = MainScreen
+    typealias Action = MainScreen.Action
 
     func render(state: State, context: RenderContext<Self>) -> Rendering {
-        let sink = context.makeSink(of: Action.self)
+        let sink = state.trampoline.makeSink(of: Action.self, with: context)
 
         return MainScreen(
             title: state.title,
-            didChangeTitle: { sink.send(.changeTitle($0)) },
+            canClose: canClose,
             allCapsToggleIsOn: state.isAllCaps,
             allCapsToggleIsEnabled: !state.title.isEmpty,
-            didChangeAllCapsToggle: { sink.send(.changeAllCaps($0)) },
-            didTapPushScreen: { sink.send(.pushScreen) },
-            didTapPresentScreen: { sink.send(.presentScreen) },
-            didTapClose: didClose
+            sink: sink
         )
     }
 }
 
+extension MainScreen.Action: WorkflowAction {
+    typealias WorkflowType = MainWorkflow
+
+    func apply(toState state: inout WorkflowType.State) -> WorkflowType.Output? {
+        switch self {
+        case .pushScreen:
+            return .pushScreen
+        case .presentScreen:
+            return .presentScreen
+        case .changeTitle(let newValue):
+            state.title = newValue
+            state.isAllCaps = newValue.isAllCaps
+        case .changeAllCaps(let isAllCaps):
+            state.isAllCaps = isAllCaps
+            state.title = isAllCaps ? state.title.uppercased() : state.title.lowercased()
+        case .close:
+            return .close
+        }
+        return nil
+    }
+}
+
 private extension String {
     var isAllCaps: Bool {
         allSatisfy { character in
@@ -89,3 +86,51 @@ private extension String {
         }
     }
 }
+
+class SinkTrampoline: Equatable {
+    private var sinks: [ObjectIdentifier: Any] = [:]
+
+    func makeSink<Action, WorkflowType>(
+        of actionType: Action.Type,
+        with context: RenderContext<WorkflowType>
+    ) -> StableSink<Action> where Action: WorkflowAction, Action.WorkflowType == WorkflowType {
+        let sink = context.makeSink(of: actionType)
+
+        sinks[ObjectIdentifier(actionType)] = sink
+
+        return StableSink(trampoline: self)
+    }
+
+    func bounce<Action>(action: Action) {
+        let sink = destination(for: Action.self)
+        sink.send(action)
+    }
+
+    private func destination<Action>(for actionType: Action.Type) -> Sink<Action> {
+        if let pipe = sinks[ObjectIdentifier(actionType)] {
+            return pipe as! Sink<Action>
+        }
+        fatalError("bad plumbing")
+    }
+
+    static func == (lhs: SinkTrampoline, rhs: SinkTrampoline) -> Bool {
+        lhs === rhs
+    }
+}
+
+struct StableSink<Action>: Equatable {
+    private var trampoline: SinkTrampoline
+
+    init(trampoline: SinkTrampoline) {
+        self.trampoline = trampoline
+    }
+
+    func send(_ action: Action) {
+        trampoline.bounce(action: action)
+    }
+
+    // sugar instead of writing { sink.send($0) }
+    func closure(_ action: Action) -> () -> Void {
+        { send(action) }
+    }
+}
diff --git a/Samples/SwiftUITestbed/Sources/RootWorkflow.swift b/Samples/SwiftUITestbed/Sources/RootWorkflow.swift
index 30db6a875..6e2117b5c 100644
--- a/Samples/SwiftUITestbed/Sources/RootWorkflow.swift
+++ b/Samples/SwiftUITestbed/Sources/RootWorkflow.swift
@@ -19,9 +19,9 @@ import Workflow
 import WorkflowUI
 
 struct RootWorkflow: Workflow {
-    let close: (() -> Void)?
-
-    typealias Output = Never
+    enum Output {
+        case close
+    }
 
     struct State {
         var backStack: BackStack
@@ -57,6 +57,8 @@ struct RootWorkflow: Workflow {
                 state.backStack.other.append(.main())
             case .main(.presentScreen):
                 state.isPresentingModal = true
+            case .main(.close):
+                return .close
             case .popScreen:
                 state.backStack.other.removeLast()
             case .dismissScreen:
@@ -75,7 +77,7 @@ struct RootWorkflow: Workflow {
         func rendering(_ screen: State.Screen, isRoot: Bool) -> AnyMarketBackStackContentScreen {
             switch screen {
             case .main(let id):
-                return MainWorkflow(didClose: isRoot ? close : nil)
+                return MainWorkflow(canClose: isRoot)
                     .mapOutput(Action.main)
                     .mapRendering(AnyMarketBackStackContentScreen.init)
                     .rendered(in: context, key: id.uuidString)
@@ -96,7 +98,13 @@ struct RootWorkflow: Workflow {
             base: backStack,
             modals: {
                 guard state.isPresentingModal else { return [] }
-                let screen = RootWorkflow(close: { sink.send(.dismissScreen) })
+                let screen = RootWorkflow()
+                    .mapOutput { output in
+                        switch output {
+                        case .close:
+                            return Action.dismissScreen
+                        }
+                    }
                     .rendered(in: context)
                     .asAnyScreen()
                 let modal = Modal(