Remove second identifier in state storage

Sources/Model/Data Flow/StateManager.swift

@@ -24,8 +24,8 @@ public enum StateManager {
     /// Information about a piece of state.
     struct State {
 
-        /// The state's identifiers.
-        var ids: (first: UUID, second: UUID?)
+        /// The state's identifier.
+        var id: UUID
         /// The state value.
         var value: Any?
         /// Whether to update in the next iteration.
@@ -35,14 +35,13 @@ public enum StateManager {
         /// - Parameter id: The identifier.
         /// - Returns: Whether the id is contained.
         func contains(id: UUID) -> Bool {
-            ids.first == id || ids.second == id
+            id == self.id
         }
 
         /// Change the identifier to a new one.
         /// - Parameter newID: The new identifier.
         mutating func changeID(new newID: UUID) {
-            ids.second = ids.first
-            ids.first = newID
+            id = newID
         }
 
     }
@@ -72,7 +71,7 @@ public enum StateManager {
     static func setState(id: UUID, value: Any?) {
         if saveState {
             guard let index = state.firstIndex(where: { $0.contains(id: id) }) else {
-                state.append(.init(ids: (first: id, second: nil), value: value))
+                state.append(.init(id: id, value: value))
                 return
             }
             state[safe: index]?.value = value

Tests/DemoApp/DemoApp.swift

@@ -1,5 +1,5 @@
 import Foundation
-import Meta
+@testable import Meta
 import Observation
 import SampleBackends
 
@@ -44,8 +44,9 @@ struct DemoView: View {
     var view: Body {
         Backend1.TestWidget1()
         Backend1.Button(model.test) {
-            model.test = "\(Int.random(in: 1...10))"
-            app.addSceneElement("main")
+            Task {
+                app.addSceneElement("main")
+            }
         }
         TestView()
         testContent
@@ -66,10 +67,7 @@ struct TestView: View {
     var view: Body {
         Backend2.TestWidget4()
         Backend1.Button(test) {
-            Task {
-                try await Task.sleep(nanoseconds: 100_000_000)
-                test = "\(Int.random(in: 1...10))"
-            }
+            test = "\(Int.random(in: 1...10))"
         }
         Backend1.Menu("Hi") {
             Backend1.Menu("World") {

Tests/SampleBackends/Backend1.swift

@@ -60,9 +60,9 @@ public enum Backend1 {
         }
 
         public func update<Storage>(_ storage: ViewStorage, modifiers: [(any AnyView) -> any AnyView], updateProperties: Bool, type: Storage.Type) {
+            storage.fields["action"] = action
             if updateProperties {
                 print("Update button (label = \(label))")
-                storage.fields["action"] = action
             } else {
                 print("Do not update button (label = \(label))")
             }