refactor and cleanup [skip ci]

submodules/Postbox/Sources/NoticeEntryView.swift

@@ -0,0 +1,31 @@
+import Foundation
+
+final class MutableNoticeEntryView {
+    private let key: NoticeEntryKey
+    fileprivate var value: NoticeEntry?
+    
+    init(accountManagerImpl: AccountManagerImpl, key: NoticeEntryKey) {
+        self.key = key
+        self.value = accountManagerImpl.noticeTable.get(key: key)
+    }
+    
+    func replay(accountManagerImpl: AccountManagerImpl, updatedKeys: Set<NoticeEntryKey>) -> Bool {
+        if updatedKeys.contains(self.key) {
+            self.value = accountManagerImpl.noticeTable.get(key: self.key)
+            return true
+        }
+        return false
+    }
+    
+    func immutableView() -> NoticeEntryView {
+        return NoticeEntryView(self)
+    }
+}
+
+public final class NoticeEntryView {
+    public let value: NoticeEntry?
+    
+    init(_ view: MutableNoticeEntryView) {
+        self.value = view.value
+    }
+}