Add HostPreferenceKey

Author: Kyle-Ye

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/HostPreferenceKey.swift

@@ -7,3 +7,7 @@
 //  Status: Complete
 
 protocol HostPreferenceKey: PreferenceKey {}
+
+extension HostPreferenceKey {
+    static var _isReadableByHost: Bool { true }
+}

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/HostPreferencesKey.swift

@@ -0,0 +1,20 @@
+//
+//  HostPreferencesKey.swift
+//  OpenSwiftUI
+//
+//  Created by Kyle on 2023/1/6.
+//  Lastest Version: iOS 15.5
+//  Status: WIP
+//  ID: 7429200566949B8FB892A77E01A988C8
+
+struct HostPreferencesKey: PreferenceKey {
+    static var defaultValue: PreferenceList {
+        PreferenceList()
+    }
+    
+    static func reduce(value: inout PreferenceList, nextValue: () -> PreferenceList) {
+        // TODO:
+    }
+    
+    private static var nodeId: UInt32 = .zero
+}