refactor and cleanup [skip ci]

submodules/Postbox/Sources/SynchronizeGroupMessageStatsView.swift

@@ -0,0 +1,41 @@
+import Foundation
+
+final class MutableSynchronizeGroupMessageStatsView: MutablePostboxView {
+    fileprivate var groupsAndNamespaces: Set<PeerGroupAndNamespace>
+    
+    init(postbox: Postbox) {
+        self.groupsAndNamespaces = postbox.synchronizeGroupMessageStatsTable.get()
+    }
+    
+    func replay(postbox: Postbox, transaction: PostboxTransaction) -> Bool {
+        var updated = false
+        if !transaction.currentUpdatedGroupSummarySynchronizeOperations.isEmpty {
+            for (groupIdAndNamespace, value) in transaction.currentUpdatedGroupSummarySynchronizeOperations {
+                if value {
+                    if !self.groupsAndNamespaces.contains(groupIdAndNamespace) {
+                        self.groupsAndNamespaces.insert(groupIdAndNamespace)
+                        updated = true
+                    }
+                } else {
+                    if self.groupsAndNamespaces.contains(groupIdAndNamespace) {
+                        self.groupsAndNamespaces.remove(groupIdAndNamespace)
+                        updated = true
+                    }
+                }
+            }
+        }
+        return updated
+    }
+    
+    func immutableView() -> PostboxView {
+        return SynchronizeGroupMessageStatsView(self)
+    }
+}
+
+public final class SynchronizeGroupMessageStatsView: PostboxView {
+    public let groupsAndNamespaces: Set<PeerGroupAndNamespace>
+    
+    init(_ view: MutableSynchronizeGroupMessageStatsView) {
+        self.groupsAndNamespaces = view.groupsAndNamespaces
+    }
+}