From b9db9809bccdebd44c786c28c8b9f067661fed09 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 11:32:25 +0800
Subject: [PATCH 01/25] container.add -> database.add

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 61dabe8a..8a6ff692 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -62,7 +62,7 @@ extension DatabaseManager {
                         modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
                             print("Resume modify records success!")
                         }
-                        self.container.add(modifyOp)
+                        self.database.add(modifyOp)
                     }
                 })
             }

From f1f98ccd14f845d97b29e19c0cea7d4313afc87d Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 11:39:01 +0800
Subject: [PATCH 02/25] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=20push=20=E9=83=A8?=
 =?UTF-8?q?=E5=88=86=20object=20=E6=96=B9=E6=B3=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 71e38444..2a3d8527 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -80,7 +80,12 @@ extension SyncEngine {
     public func pushAll() {
         databaseManager.syncObjects.forEach { $0.pushLocalObjectsToCloudKit() }
     }
-    
+
+    public func push(objects: [CKRecordConvertible], completionHandler: ((Error?) -> Void)? = nil) {
+        let recordsToStore: [CKRecord] = objects.filter { !$0.isDeleted }.map { $0.record }
+        let recordsIDsToDelete: [CKRecord.ID] = objects.filter { $0.isDeleted }.map { $0.recordID }
+        databaseManager.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordsIDsToDelete, completion: completionHandler)
+    }
 }
 
 public enum Notifications: String, NotificationName {

From fd447b29b7f01cc30131f0f56875a26aa1516028 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 12:28:59 +0800
Subject: [PATCH 03/25] =?UTF-8?q?pushAll=20=E9=80=89=E6=8B=A9=E7=B1=BB?=
 =?UTF-8?q?=E5=9E=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 2a3d8527..d1a3875c 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -77,8 +77,9 @@ extension SyncEngine {
     
     /// Push all existing local data to CloudKit
     /// You should NOT to call this method too frequently
-    public func pushAll() {
-        databaseManager.syncObjects.forEach { $0.pushLocalObjectsToCloudKit() }
+    public func pushAll(objects: [Syncable]? = nil) {
+        let objects = objects?.filter(databaseManager.syncObjects.contains($0)) ?? databaseManager.syncObjects
+        objects.forEach { $0.pushLocalObjectsToCloudKit() }
     }
 
     public func push(objects: [CKRecordConvertible], completionHandler: ((Error?) -> Void)? = nil) {

From 03508c8e70ede3d8cd0bfa980816be2fb191f26d Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 12:30:32 +0800
Subject: [PATCH 04/25] =?UTF-8?q?=E5=8E=BB=E6=8E=89=E5=88=A4=E6=96=AD?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index d1a3875c..513eaa04 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -78,8 +78,7 @@ extension SyncEngine {
     /// Push all existing local data to CloudKit
     /// You should NOT to call this method too frequently
     public func pushAll(objects: [Syncable]? = nil) {
-        let objects = objects?.filter(databaseManager.syncObjects.contains($0)) ?? databaseManager.syncObjects
-        objects.forEach { $0.pushLocalObjectsToCloudKit() }
+        (objects ?? databaseManager.syncObjects).forEach { $0.pushLocalObjectsToCloudKit() }
     }
 
     public func push(objects: [CKRecordConvertible], completionHandler: ((Error?) -> Void)? = nil) {

From 057486ef7d95ea5cd38e4bc7fb799388efee5e17 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 12:36:58 +0800
Subject: [PATCH 05/25] =?UTF-8?q?=E8=BF=98=E6=98=AF=E4=B8=8D=E4=BF=AE?=
 =?UTF-8?q?=E6=94=B9=20pushAll=20=E4=BA=86?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 513eaa04..2a3d8527 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -77,8 +77,8 @@ extension SyncEngine {
     
     /// Push all existing local data to CloudKit
     /// You should NOT to call this method too frequently
-    public func pushAll(objects: [Syncable]? = nil) {
-        (objects ?? databaseManager.syncObjects).forEach { $0.pushLocalObjectsToCloudKit() }
+    public func pushAll() {
+        databaseManager.syncObjects.forEach { $0.pushLocalObjectsToCloudKit() }
     }
 
     public func push(objects: [CKRecordConvertible], completionHandler: ((Error?) -> Void)? = nil) {

From 923bed31f46198d95807ef7278bba1bb8748b2a8 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 13:26:59 +0800
Subject: [PATCH 06/25] database -> container //
 https://developer.apple.com/documentation/cloudkit/ckoperation\#1666033

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 8a6ff692..61dabe8a 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -62,7 +62,7 @@ extension DatabaseManager {
                         modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
                             print("Resume modify records success!")
                         }
-                        self.database.add(modifyOp)
+                        self.container.add(modifyOp)
                     }
                 })
             }

From 21cad102f13d1187f38b5c9fb190556878a5fa29 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 13:29:52 +0800
Subject: [PATCH 07/25] =?UTF-8?q?iOS=2015=20=E4=B8=8D=E5=86=8D=E5=A4=84?=
 =?UTF-8?q?=E7=90=86=20long=20lived=20operation?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Classes/DatabaseManagerProtocol.swift     | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 61dabe8a..8980830c 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -53,18 +53,22 @@ extension DatabaseManager {
     }
     
     func resumeLongLivedOperationIfPossible() {
-        container.fetchAllLongLivedOperationIDs { [weak self]( opeIDs, error) in
-            guard let self = self, error == nil, let ids = opeIDs else { return }
-            for id in ids {
-                self.container.fetchLongLivedOperation(withID: id, completionHandler: { [weak self](ope, error) in
-                    guard let self = self, error == nil else { return }
-                    if let modifyOp = ope as? CKModifyRecordsOperation {
-                        modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
-                            print("Resume modify records success!")
+        if #available(iOS 15.0) {
+            // do nothing.
+        } else {
+            container.fetchAllLongLivedOperationIDs { [weak self]( opeIDs, error) in
+                guard let self = self, error == nil, let ids = opeIDs else { return }
+                for id in ids {
+                    self.container.fetchLongLivedOperation(withID: id, completionHandler: { [weak self](ope, error) in
+                        guard let self = self, error == nil else { return }
+                        if let modifyOp = ope as? CKModifyRecordsOperation {
+                            modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
+                                print("Resume modify records success!")
+                            }
+                            self.container.add(modifyOp)
                         }
-                        self.container.add(modifyOp)
-                    }
-                })
+                    })
+                }
             }
         }
     }

From 148a908933f63c8ba45537e14196ff03f58376e0 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 29 Jul 2021 13:30:54 +0800
Subject: [PATCH 08/25] =?UTF-8?q?=E6=81=A2=E5=A4=8D=E8=BF=99=E4=B8=AA?=
 =?UTF-8?q?=E5=86=99=E6=B3=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 8980830c..e1da63ab 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -53,7 +53,7 @@ extension DatabaseManager {
     }
     
     func resumeLongLivedOperationIfPossible() {
-        if #available(iOS 15.0) {
+        if #available(iOS 15.0, *) {
             // do nothing.
         } else {
             container.fetchAllLongLivedOperationIDs { [weak self]( opeIDs, error) in

From 4a4dbe858c1888a984db8d032727733f171f37de Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 26 Aug 2021 17:10:21 +0800
Subject: [PATCH 09/25] =?UTF-8?q?=E5=88=9D=E5=A7=8B=E5=8C=96=E6=97=B6?=
 =?UTF-8?q?=E5=A2=9E=E5=8A=A0=20pull=20=E7=9A=84=E5=9B=9E=E8=B0=83?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 2a3d8527..e7f947a5 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -17,25 +17,25 @@ public final class SyncEngine {
     
     private let databaseManager: DatabaseManager
     
-    public convenience init(objects: [Syncable], databaseScope: CKDatabase.Scope = .private, container: CKContainer = .default()) {
+    public convenience init(objects: [Syncable], databaseScope: CKDatabase.Scope = .private, container: CKContainer = .default(), callback: ((Error?) -> Void)? = nil) {
         switch databaseScope {
         case .private:
             let privateDatabaseManager = PrivateDatabaseManager(objects: objects, container: container)
-            self.init(databaseManager: privateDatabaseManager)
+            self.init(databaseManager: privateDatabaseManager, callback: callback)
         case .public:
             let publicDatabaseManager = PublicDatabaseManager(objects: objects, container: container)
-            self.init(databaseManager: publicDatabaseManager)
+            self.init(databaseManager: publicDatabaseManager, callback: callback)
         default:
             fatalError("Shared database scope is not supported yet")
         }
     }
     
-    private init(databaseManager: DatabaseManager) {
+    private init(databaseManager: DatabaseManager, callback: ((Error?) -> Void)?) {
         self.databaseManager = databaseManager
-        setup()
+        setup(callback)
     }
     
-    private func setup() {
+    private func setup(_ callback: ((Error?) -> Void)?) {
         databaseManager.prepare()
         databaseManager.container.accountStatus { [weak self] (status, error) in
             guard let self = self else { return }
@@ -43,20 +43,22 @@ public final class SyncEngine {
             case .available:
                 self.databaseManager.registerLocalDatabase()
                 self.databaseManager.createCustomZonesIfAllowed()
-                self.databaseManager.fetchChangesInDatabase(nil)
+                self.databaseManager.fetchChangesInDatabase(callback)
                 self.databaseManager.resumeLongLivedOperationIfPossible()
                 self.databaseManager.startObservingRemoteChanges()
                 self.databaseManager.startObservingTermination()
                 self.databaseManager.createDatabaseSubscriptionIfHaveNot()
             case .noAccount, .restricted:
                 guard self.databaseManager is PublicDatabaseManager else { break }
-                self.databaseManager.fetchChangesInDatabase(nil)
+                self.databaseManager.fetchChangesInDatabase(callback)
                 self.databaseManager.resumeLongLivedOperationIfPossible()
                 self.databaseManager.startObservingRemoteChanges()
                 self.databaseManager.startObservingTermination()
                 self.databaseManager.createDatabaseSubscriptionIfHaveNot()
             case .couldNotDetermine:
                 break
+            case .temporarilyUnavailable:
+                break
             @unknown default:
                 break
             }

From 24a73df6b053a51fd2b61f94bf1cf5240e54e8c8 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 2 Sep 2021 15:41:37 +0800
Subject: [PATCH 10/25] =?UTF-8?q?iOS=2015=20=E4=B8=8E=E5=85=B6=E4=BB=96?=
 =?UTF-8?q?=E7=89=88=E6=9C=AC=E5=8C=BA=E5=88=86=E5=A4=84=E7=90=86=20longLi?=
 =?UTF-8?q?veOperation?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Classes/DatabaseManagerProtocol.swift     | 28 +++++++++----------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index e1da63ab..c0c19358 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -53,22 +53,22 @@ extension DatabaseManager {
     }
     
     func resumeLongLivedOperationIfPossible() {
-        if #available(iOS 15.0, *) {
-            // do nothing.
-        } else {
-            container.fetchAllLongLivedOperationIDs { [weak self]( opeIDs, error) in
-                guard let self = self, error == nil, let ids = opeIDs else { return }
-                for id in ids {
-                    self.container.fetchLongLivedOperation(withID: id, completionHandler: { [weak self](ope, error) in
-                        guard let self = self, error == nil else { return }
-                        if let modifyOp = ope as? CKModifyRecordsOperation {
-                            modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
-                                print("Resume modify records success!")
-                            }
+        container.fetchAllLongLivedOperationIDs { [weak self]( opeIDs, error) in
+            guard let self = self, error == nil, let ids = opeIDs else { return }
+            for id in ids {
+                self.container.fetchLongLivedOperation(withID: id, completionHandler: { [weak self](ope, error) in
+                    guard let self = self, error == nil else { return }
+                    if let modifyOp = ope as? CKModifyRecordsOperation {
+                        modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
+                            print("Resume modify records success!")
+                        }
+                        if #available(iOS 15, *) {
+                            self.database.add(modifyOp)
+                        } else {
                             self.container.add(modifyOp)
                         }
-                    })
-                }
+                    }
+                })
             }
         }
     }

From f9c554575e7d3701cfc0244bb1d0505d7a280ef1 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 2 Sep 2021 15:44:15 +0800
Subject: [PATCH 11/25] =?UTF-8?q?=E5=8E=BB=E6=8E=89=20iOS=2015=20=E4=BB=A5?=
 =?UTF-8?q?=E5=89=8D=E6=B2=A1=E6=9C=89=E7=9A=84=20case?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 2 --
 1 file changed, 2 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index e7f947a5..3a22e357 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -57,8 +57,6 @@ public final class SyncEngine {
                 self.databaseManager.createDatabaseSubscriptionIfHaveNot()
             case .couldNotDetermine:
                 break
-            case .temporarilyUnavailable:
-                break
             @unknown default:
                 break
             }

From b2ae85230b1499f4e57f5e1ddc0c4d44143d5261 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Tue, 7 Sep 2021 18:33:12 +0800
Subject: [PATCH 12/25] =?UTF-8?q?=E6=8F=90=E4=BE=9B=E6=9A=82=E5=81=9C?=
 =?UTF-8?q?=E7=9B=91=E5=90=AC=20changes=20=E9=80=9A=E7=9F=A5=E6=96=B9?=
 =?UTF-8?q?=E6=B3=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift |  5 ++++-
 IceCream/Classes/PrivateDatabaseManager.swift  | 18 +++++++++++++++---
 IceCream/Classes/PublicDatabaseManager.swift   | 12 +++++++++++-
 IceCream/Classes/SyncEngine.swift              |  8 ++++++++
 IceCream/Classes/SyncObject.swift              |  6 ++++++
 IceCream/Classes/Syncable.swift                |  1 +
 6 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index c0c19358..536630fe 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -37,6 +37,7 @@ protocol DatabaseManager: class {
     func startObservingTermination()
     func createDatabaseSubscriptionIfHaveNot()
     func registerLocalDatabase()
+    func unregisterLocalDatabase()
     
     func cleanUp()
 }
@@ -63,6 +64,7 @@ extension DatabaseManager {
                             print("Resume modify records success!")
                         }
                         if #available(iOS 15, *) {
+                            print("Add operation: fetchLongLivedOperation")
                             self.database.add(modifyOp)
                         } else {
                             self.container.add(modifyOp)
@@ -131,7 +133,8 @@ extension DatabaseManager {
                 return
             }
         }
-        
+
+        print("Add operation: syncRecordsToCloudKit")
         database.add(modifyOpe)
     }
     
diff --git a/IceCream/Classes/PrivateDatabaseManager.swift b/IceCream/Classes/PrivateDatabaseManager.swift
index 071c5423..e8fb5e3a 100644
--- a/IceCream/Classes/PrivateDatabaseManager.swift
+++ b/IceCream/Classes/PrivateDatabaseManager.swift
@@ -60,7 +60,8 @@ final class PrivateDatabaseManager: DatabaseManager {
                 return
             }
         }
-        
+
+        print("Add operation: fetchChangesInDatabase")
         database.add(changesOperation)
     }
     
@@ -90,7 +91,8 @@ final class PrivateDatabaseManager: DatabaseManager {
                 return
             }
         }
-        
+
+        print("Add operation: createCustomZonesIfAllowed")
         database.add(modifyOp)
     }
     
@@ -110,6 +112,7 @@ final class PrivateDatabaseManager: DatabaseManager {
             self.subscriptionIsLocallyCached = true
         }
         createOp.qualityOfService = .utility
+        print("Add operation: createDatabaseSubscriptionIfHaveNot")
         database.add(createOp)
         #endif
     }
@@ -133,6 +136,14 @@ final class PrivateDatabaseManager: DatabaseManager {
             }
         }
     }
+
+    func unregisterLocalDatabase() {
+        self.syncObjects.forEach { object in
+            DispatchQueue.main.async {
+                object.unregisterLocalDatabase()
+            }
+        }
+    }
     
     private func fetchChangesInZones(_ callback: ((Error?) -> Void)? = nil) {
         let changesOp = CKFetchRecordZoneChangesOperation(recordZoneIDs: zoneIds, optionsByRecordZoneID: zoneIdOptions)
@@ -190,7 +201,8 @@ final class PrivateDatabaseManager: DatabaseManager {
             }
             callback?(error)
         }
-        
+
+        print("Add operation: fetchChangesInZones")
         database.add(changesOp)
     }
 }
diff --git a/IceCream/Classes/PublicDatabaseManager.swift b/IceCream/Classes/PublicDatabaseManager.swift
index ff901701..c6de6223 100644
--- a/IceCream/Classes/PublicDatabaseManager.swift
+++ b/IceCream/Classes/PublicDatabaseManager.swift
@@ -62,6 +62,14 @@ final class PublicDatabaseManager: DatabaseManager {
             }
         }
     }
+
+    func unregisterLocalDatabase() {
+        self.syncObjects.forEach { object in
+            DispatchQueue.main.async {
+                object.unregisterLocalDatabase()
+            }
+        }
+    }
     
     // MARK: - Private Methods
     private func excuteQueryOperation(queryOperation: CKQueryOperation,on syncObject: Syncable, callback: ((Error?) -> Void)? = nil) {
@@ -89,7 +97,8 @@ final class PublicDatabaseManager: DatabaseManager {
                 break
             }
         }
-        
+
+        print("Add operation: excuteQueryOperation")
         database.add(queryOperation)
     }
     
@@ -108,6 +117,7 @@ final class PublicDatabaseManager: DatabaseManager {
             
         }
         createOp.qualityOfService = .utility
+        print("Add operation: createSubscriptionInPublicDatabase")
         database.add(createOp)
         #endif
     }
diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 3a22e357..4537a574 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -86,6 +86,14 @@ extension SyncEngine {
         let recordsIDsToDelete: [CKRecord.ID] = objects.filter { $0.isDeleted }.map { $0.recordID }
         databaseManager.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordsIDsToDelete, completion: completionHandler)
     }
+
+    public func registerLocalDatabase() {
+        databaseManager.registerLocalDatabase()
+    }
+
+    public func unregisterLocalDatabase() {
+        databaseManager.unregisterLocalDatabase()
+    }
 }
 
 public enum Notifications: String, NotificationName {
diff --git a/IceCream/Classes/SyncObject.swift b/IceCream/Classes/SyncObject.swift
index 8a74b6de..1fe31a13 100644
--- a/IceCream/Classes/SyncObject.swift
+++ b/IceCream/Classes/SyncObject.swift
@@ -150,6 +150,12 @@ extension SyncObject: Syncable {
             })
         }
     }
+
+    public func unregisterLocalDatabase() {
+        BackgroundWorker.shared.start {
+            self.notificationToken = nil
+        }
+    }
     
     public func resolvePendingRelationships() {
         pendingUTypeRelationshipsWorker.resolvePendingListElements()
diff --git a/IceCream/Classes/Syncable.swift b/IceCream/Classes/Syncable.swift
index 4b1568b0..b1457c18 100644
--- a/IceCream/Classes/Syncable.swift
+++ b/IceCream/Classes/Syncable.swift
@@ -23,6 +23,7 @@ public protocol Syncable: class {
     
     /// Realm Database related
     func registerLocalDatabase()
+    func unregisterLocalDatabase()
     func cleanUp()
     func add(record: CKRecord)
     func delete(recordID: CKRecord.ID)

From e82c6f2b42bfd9ec0956c0bc9888a65acc24cf89 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Wed, 8 Sep 2021 17:48:40 +0800
Subject: [PATCH 13/25] =?UTF-8?q?=E4=B8=BA=E4=BA=86=E8=83=BD=E8=BF=90?=
 =?UTF-8?q?=E8=A1=8C=EF=BC=8C=E4=B8=8D=20Resume=20Long=20Lived=20Operaiton?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 536630fe..fe6806c1 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -65,7 +65,7 @@ extension DatabaseManager {
                         }
                         if #available(iOS 15, *) {
                             print("Add operation: fetchLongLivedOperation")
-                            self.database.add(modifyOp)
+                            // self.database.add(modifyOp)
                         } else {
                             self.container.add(modifyOp)
                         }

From 9030be671a140b65db1f86605e26c4041affe1d2 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 14:50:50 +0800
Subject: [PATCH 14/25] =?UTF-8?q?=E5=88=9D=E5=A7=8B=E5=8C=96=20SyncEngine?=
 =?UTF-8?q?=20=E6=97=B6=EF=BC=8C=E6=94=AF=E6=8C=81=E4=B8=8D=E5=BC=80?=
 =?UTF-8?q?=E5=A7=8B=E5=90=8C=E6=AD=A5?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Example/IceCream_Example/AppDelegate.swift    | 15 +++++---
 .../Classes/DatabaseManagerProtocol.swift     |  6 +++
 IceCream/Classes/PrivateDatabaseManager.swift | 12 ++++++
 IceCream/Classes/PublicDatabaseManager.swift  | 12 ++++++
 IceCream/Classes/SyncEngine.swift             | 38 ++++++++++++-------
 5 files changed, 64 insertions(+), 19 deletions(-)

diff --git a/Example/IceCream_Example/AppDelegate.swift b/Example/IceCream_Example/AppDelegate.swift
index 937fdd27..24667a63 100644
--- a/Example/IceCream_Example/AppDelegate.swift
+++ b/Example/IceCream_Example/AppDelegate.swift
@@ -19,11 +19,16 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         
-        syncEngine = SyncEngine(objects: [
-            SyncObject(type: Dog.self),
-            SyncObject(type: Cat.self),
-            SyncObject(type: Person.self, uListElementType: Cat.self)
-            ])
+        syncEngine = SyncEngine(
+            objects: [
+                SyncObject(type: Dog.self),
+                SyncObject(type: Cat.self),
+                SyncObject(type: Person.self, uListElementType: Cat.self)
+            ],
+            callback: { syncEngine in
+                syncEngine.pull(completionHandler: nil)
+                syncEngine.startObservingLocalAndRemoteChanges()
+            })
         
         /// If you wanna test public Database, comment the above syncEngine code and uncomment the following one
         /// Besides, uncomment Line 26 to 28 in Person.swift file
diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index fe6806c1..42ae1a55 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -34,7 +34,9 @@ protocol DatabaseManager: class {
     
     func createCustomZonesIfAllowed()
     func startObservingRemoteChanges()
+    func stopObservingRemoteChanges()
     func startObservingTermination()
+    func stopObservingTermination()
     func createDatabaseSubscriptionIfHaveNot()
     func registerLocalDatabase()
     func unregisterLocalDatabase()
@@ -83,6 +85,10 @@ extension DatabaseManager {
             }
         })
     }
+
+    func stopObservingRemoteChanges() {
+        NotificationCenter.default.removeObserver(self, name: Notifications.cloudKitDataDidChangeRemotely.name, object: nil)
+    }
     
     /// Sync local data to CloudKit
     /// For more about the savePolicy: https://developer.apple.com/documentation/cloudkit/ckrecordsavepolicy
diff --git a/IceCream/Classes/PrivateDatabaseManager.swift b/IceCream/Classes/PrivateDatabaseManager.swift
index e8fb5e3a..adb69bd8 100644
--- a/IceCream/Classes/PrivateDatabaseManager.swift
+++ b/IceCream/Classes/PrivateDatabaseManager.swift
@@ -128,6 +128,18 @@ final class PrivateDatabaseManager: DatabaseManager {
         
         #endif
     }
+
+    func stopObservingTermination() {
+        #if os(iOS) || os(tvOS)
+
+        NotificationCenter.default.removeObserver(self, name: UIApplication.willTerminateNotification, object: nil)
+
+        #elseif os(macOS)
+
+        NotificationCenter.default.removeObserver(self, name: NSApplication.willTerminateNotification, object: nil)
+
+        #endif
+    }
     
     func registerLocalDatabase() {
         self.syncObjects.forEach { object in
diff --git a/IceCream/Classes/PublicDatabaseManager.swift b/IceCream/Classes/PublicDatabaseManager.swift
index c6de6223..fbcee2c1 100644
--- a/IceCream/Classes/PublicDatabaseManager.swift
+++ b/IceCream/Classes/PublicDatabaseManager.swift
@@ -54,6 +54,18 @@ final class PublicDatabaseManager: DatabaseManager {
         
         #endif
     }
+
+    func stopObservingTermination() {
+        #if os(iOS) || os(tvOS)
+
+        NotificationCenter.default.removeObserver(self, name: UIApplication.willTerminateNotification, object: nil)
+
+        #elseif os(macOS)
+
+        NotificationCenter.default.removeObserver(self, name: NSApplication.willTerminateNotification, object: nil)
+
+        #endif
+    }
     
     func registerLocalDatabase() {
         syncObjects.forEach { object in
diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 4537a574..8249f3a5 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -17,7 +17,7 @@ public final class SyncEngine {
     
     private let databaseManager: DatabaseManager
     
-    public convenience init(objects: [Syncable], databaseScope: CKDatabase.Scope = .private, container: CKContainer = .default(), callback: ((Error?) -> Void)? = nil) {
+    public convenience init(objects: [Syncable], databaseScope: CKDatabase.Scope = .private, container: CKContainer = .default(), callback: @escaping (SyncEngine) -> Void) {
         switch databaseScope {
         case .private:
             let privateDatabaseManager = PrivateDatabaseManager(objects: objects, container: container)
@@ -30,31 +30,33 @@ public final class SyncEngine {
         }
     }
     
-    private init(databaseManager: DatabaseManager, callback: ((Error?) -> Void)?) {
+    private init(databaseManager: DatabaseManager, callback: @escaping (SyncEngine) -> Void) {
         self.databaseManager = databaseManager
         setup(callback)
     }
     
-    private func setup(_ callback: ((Error?) -> Void)?) {
+    private func setup(_ callback: @escaping (SyncEngine) -> Void) {
         databaseManager.prepare()
         databaseManager.container.accountStatus { [weak self] (status, error) in
             guard let self = self else { return }
             switch status {
             case .available:
-                self.databaseManager.registerLocalDatabase()
+                // self.databaseManager.registerLocalDatabase()
                 self.databaseManager.createCustomZonesIfAllowed()
-                self.databaseManager.fetchChangesInDatabase(callback)
+                // self.databaseManager.fetchChangesInDatabase(callback)
                 self.databaseManager.resumeLongLivedOperationIfPossible()
-                self.databaseManager.startObservingRemoteChanges()
-                self.databaseManager.startObservingTermination()
+                // self.databaseManager.startObservingRemoteChanges()
+                // self.databaseManager.startObservingTermination()
                 self.databaseManager.createDatabaseSubscriptionIfHaveNot()
+                callback(self)
             case .noAccount, .restricted:
                 guard self.databaseManager is PublicDatabaseManager else { break }
-                self.databaseManager.fetchChangesInDatabase(callback)
+                // self.databaseManager.fetchChangesInDatabase(callback)
                 self.databaseManager.resumeLongLivedOperationIfPossible()
-                self.databaseManager.startObservingRemoteChanges()
-                self.databaseManager.startObservingTermination()
+                // self.databaseManager.startObservingRemoteChanges()
+                // self.databaseManager.startObservingTermination()
                 self.databaseManager.createDatabaseSubscriptionIfHaveNot()
+                callback(self)
             case .couldNotDetermine:
                 break
             @unknown default:
@@ -87,12 +89,20 @@ extension SyncEngine {
         databaseManager.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordsIDsToDelete, completion: completionHandler)
     }
 
-    public func registerLocalDatabase() {
-        databaseManager.registerLocalDatabase()
+    public func startObservingLocalAndRemoteChanges() {
+        if self.databaseManager is PrivateDatabaseManager {
+            databaseManager.registerLocalDatabase()
+        }
+        databaseManager.startObservingRemoteChanges()
+        databaseManager.startObservingTermination()
     }
 
-    public func unregisterLocalDatabase() {
-        databaseManager.unregisterLocalDatabase()
+    public func stopObservingLocalAndRemoteChanges() {
+        if self.databaseManager is PrivateDatabaseManager {
+            databaseManager.unregisterLocalDatabase()
+        }
+        databaseManager.stopObservingRemoteChanges()
+        databaseManager.stopObservingTermination()
     }
 }
 

From 7c0020fd4baf09d21a717a39ef4f14a08640238d Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 15:00:17 +0800
Subject: [PATCH 15/25] =?UTF-8?q?=E9=81=BF=E5=85=8D=E4=B8=BA=20notificatio?=
 =?UTF-8?q?n=20=E5=A2=9E=E5=8A=A0=E5=A4=9A=E4=B8=AA=20obsever?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/SyncEngine.swift | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 8249f3a5..4e1ebf59 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -90,6 +90,8 @@ extension SyncEngine {
     }
 
     public func startObservingLocalAndRemoteChanges() {
+        stopObservingLocalAndRemoteChanges() // Avoid add observer for multiple times.
+
         if self.databaseManager is PrivateDatabaseManager {
             databaseManager.registerLocalDatabase()
         }

From 4ef748bea18d0fbd32d70ca8da1867f46566eea5 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 15:35:27 +0800
Subject: [PATCH 16/25] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=20debug=20=E8=BE=93?=
 =?UTF-8?q?=E5=87=BA?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Classes/DatabaseManagerProtocol.swift     |  6 ++---
 IceCream/Classes/PrivateDatabaseManager.swift | 22 +++++++++++++++----
 IceCream/Classes/PublicDatabaseManager.swift  |  4 ++--
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 42ae1a55..770bbd48 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -63,10 +63,10 @@ extension DatabaseManager {
                     guard let self = self, error == nil else { return }
                     if let modifyOp = ope as? CKModifyRecordsOperation {
                         modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
-                            print("Resume modify records success!")
+                            print("🍦 Resume modify records success!")
                         }
                         if #available(iOS 15, *) {
-                            print("Add operation: fetchLongLivedOperation")
+                            print("🍦 Add operation: fetchLongLivedOperation")
                             // self.database.add(modifyOp)
                         } else {
                             self.container.add(modifyOp)
@@ -140,7 +140,7 @@ extension DatabaseManager {
             }
         }
 
-        print("Add operation: syncRecordsToCloudKit")
+        print("🍦 Add operation: syncRecordsToCloudKit")
         database.add(modifyOpe)
     }
     
diff --git a/IceCream/Classes/PrivateDatabaseManager.swift b/IceCream/Classes/PrivateDatabaseManager.swift
index adb69bd8..14c0d155 100644
--- a/IceCream/Classes/PrivateDatabaseManager.swift
+++ b/IceCream/Classes/PrivateDatabaseManager.swift
@@ -31,6 +31,7 @@ final class PrivateDatabaseManager: DatabaseManager {
         
         /// Only update the changeToken when fetch process completes
         changesOperation.changeTokenUpdatedBlock = { [weak self] newToken in
+            print("🍦 Database change token updated")
             self?.databaseChangeToken = newToken
         }
         
@@ -40,28 +41,33 @@ final class PrivateDatabaseManager: DatabaseManager {
             guard let self = self else { return }
             switch ErrorHandler.shared.resultType(with: error) {
             case .success:
+                print("🍦 Database fetch completed, token updated")
                 self.databaseChangeToken = newToken
                 // Fetch the changes in zone level
                 self.fetchChangesInZones(callback)
             case .retry(let timeToWait, _):
+                print("🍦 Database fetch needs retry")
                 ErrorHandler.shared.retryOperationIfPossible(retryAfter: timeToWait, block: {
                     self.fetchChangesInDatabase(callback)
                 })
             case .recoverableError(let reason, _):
                 switch reason {
                 case .changeTokenExpired:
+                    print("🍦 Database fetch token expired")
                     /// The previousServerChangeToken value is too old and the client must re-sync from scratch
                     self.databaseChangeToken = nil
                     self.fetchChangesInDatabase(callback)
                 default:
+                    print("🍦 Database fetch unhandled recoverable error: \(reason)")
                     return
                 }
             default:
+                print("🍦 Database unhandled completion: \(error.debugDescription)")
                 return
             }
         }
 
-        print("Add operation: fetchChangesInDatabase")
+        print("🍦 Add operation: fetchChangesInDatabase")
         database.add(changesOperation)
     }
     
@@ -92,7 +98,7 @@ final class PrivateDatabaseManager: DatabaseManager {
             }
         }
 
-        print("Add operation: createCustomZonesIfAllowed")
+        print("🍦 Add operation: createCustomZonesIfAllowed")
         database.add(modifyOp)
     }
     
@@ -112,7 +118,7 @@ final class PrivateDatabaseManager: DatabaseManager {
             self.subscriptionIsLocallyCached = true
         }
         createOp.qualityOfService = .utility
-        print("Add operation: createDatabaseSubscriptionIfHaveNot")
+        print("🍦 Add operation: createDatabaseSubscriptionIfHaveNot")
         database.add(createOp)
         #endif
     }
@@ -162,6 +168,7 @@ final class PrivateDatabaseManager: DatabaseManager {
         changesOp.fetchAllChanges = true
         
         changesOp.recordZoneChangeTokensUpdatedBlock = { [weak self] zoneId, token, _ in
+            print("🍦 Record zone \(zoneId) change token updated")
             guard let self = self else { return }
             guard let syncObject = self.syncObjects.first(where: { $0.zoneID == zoneId }) else { return }
             syncObject.zoneChangesToken = token
@@ -170,12 +177,14 @@ final class PrivateDatabaseManager: DatabaseManager {
         changesOp.recordChangedBlock = { [weak self] record in
             /// The Cloud will return the modified record since the last zoneChangesToken, we need to do local cache here.
             /// Handle the record:
+            print("🍦 Record zone \(record.recordID) changed")
             guard let self = self else { return }
             guard let syncObject = self.syncObjects.first(where: { $0.recordType == record.recordType }) else { return }
             syncObject.add(record: record)
         }
         
         changesOp.recordWithIDWasDeletedBlock = { [weak self] recordId, _ in
+            print("🍦 Record \(recordId) deleted")
             guard let self = self else { return }
             guard let syncObject = self.syncObjects.first(where: { $0.zoneID == recordId.zoneID }) else { return }
             syncObject.delete(recordID: recordId)
@@ -185,23 +194,28 @@ final class PrivateDatabaseManager: DatabaseManager {
             guard let self = self else { return }
             switch ErrorHandler.shared.resultType(with: error) {
             case .success:
+                print("🍦 Record zone \(zoneId) fetch completed, token updated")
                 guard let syncObject = self.syncObjects.first(where: { $0.zoneID == zoneId }) else { return }
                 syncObject.zoneChangesToken = token
             case .retry(let timeToWait, _):
+                print("🍦 Record zone \(zoneId) fetch needs retry")
                 ErrorHandler.shared.retryOperationIfPossible(retryAfter: timeToWait, block: {
                     self.fetchChangesInZones(callback)
                 })
             case .recoverableError(let reason, _):
                 switch reason {
                 case .changeTokenExpired:
+                    print("🍦 Record zone \(zoneId) token expired")
                     /// The previousServerChangeToken value is too old and the client must re-sync from scratch
                     guard let syncObject = self.syncObjects.first(where: { $0.zoneID == zoneId }) else { return }
                     syncObject.zoneChangesToken = nil
                     self.fetchChangesInZones(callback)
                 default:
+                    print("🍦 Record zone \(zoneId) unhandled recoverable error: \(reason)")
                     return
                 }
             default:
+                print("🍦 Record zone \(zoneId) unhandled completion: \(error.debugDescription)")
                 return
             }
         }
@@ -214,7 +228,7 @@ final class PrivateDatabaseManager: DatabaseManager {
             callback?(error)
         }
 
-        print("Add operation: fetchChangesInZones")
+        print("🍦 Add operation: fetchChangesInZones")
         database.add(changesOp)
     }
 }
diff --git a/IceCream/Classes/PublicDatabaseManager.swift b/IceCream/Classes/PublicDatabaseManager.swift
index fbcee2c1..171337bc 100644
--- a/IceCream/Classes/PublicDatabaseManager.swift
+++ b/IceCream/Classes/PublicDatabaseManager.swift
@@ -110,7 +110,7 @@ final class PublicDatabaseManager: DatabaseManager {
             }
         }
 
-        print("Add operation: excuteQueryOperation")
+        print("🍦 Add operation: excuteQueryOperation")
         database.add(queryOperation)
     }
     
@@ -129,7 +129,7 @@ final class PublicDatabaseManager: DatabaseManager {
             
         }
         createOp.qualityOfService = .utility
-        print("Add operation: createSubscriptionInPublicDatabase")
+        print("🍦 Add operation: createSubscriptionInPublicDatabase")
         database.add(createOp)
         #endif
     }

From 0e14130201de5313ab8e1160b5f9a02389d27cbf Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 15:37:48 +0800
Subject: [PATCH 17/25] =?UTF-8?q?Push=20=E6=95=B0=E6=8D=AE=E5=A2=9E?=
 =?UTF-8?q?=E5=8A=A0=20debug?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 770bbd48..c52ad8a7 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -121,14 +121,17 @@ extension DatabaseManager {
             
             switch ErrorHandler.shared.resultType(with: error) {
             case .success:
+                print("🍦 Modify record completed")
                 DispatchQueue.main.async {
                     completion?(nil)
                 }
             case .retry(let timeToWait, _):
+                print("🍦 Modify record needs retry")
                 ErrorHandler.shared.retryOperationIfPossible(retryAfter: timeToWait) {
                     self.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordIDsToDelete, completion: completion)
                 }
             case .chunk:
+                print("🍦 Modify record needs chunk")
                 /// CloudKit says maximum number of items in a single request is 400.
                 /// So I think 300 should be fine by them.
                 let chunkedRecords = recordsToStore.chunkItUp(by: 300)
@@ -136,6 +139,7 @@ extension DatabaseManager {
                     self.syncRecordsToCloudKit(recordsToStore: chunk, recordIDsToDelete: recordIDsToDelete, completion: completion)
                 }
             default:
+                print("🍦 Modify record unhandled completion: \(error.debugDescription)")
                 return
             }
         }

From b7d11bc77ab28eb3f05a464951d0b530dc7a59be Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 16:13:37 +0800
Subject: [PATCH 18/25] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=E4=BF=9D=E5=AD=98?=
 =?UTF-8?q?=E7=9A=84=E8=AE=B0=E5=BD=95=E6=95=B0=E9=87=8F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index c52ad8a7..dbea8740 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -144,7 +144,7 @@ extension DatabaseManager {
             }
         }
 
-        print("🍦 Add operation: syncRecordsToCloudKit")
+        print("🍦 Add operation: syncRecordsToCloudKit store \(recordsToStore.count) \(recordsToStore.first?.recordType ?? "unknown") objects, delete \(recordIDsToDelete.count) objects")
         database.add(modifyOpe)
     }
     

From 8c444b5f5b911bfb0233f27e1635811b2c1e8f21 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Thu, 9 Sep 2021 19:14:18 +0800
Subject: [PATCH 19/25] =?UTF-8?q?=E6=81=A2=E5=A4=8D=20add=20long=20lived?=
 =?UTF-8?q?=20operation?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index dbea8740..0d1cd43c 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -67,7 +67,7 @@ extension DatabaseManager {
                         }
                         if #available(iOS 15, *) {
                             print("🍦 Add operation: fetchLongLivedOperation")
-                            // self.database.add(modifyOp)
+                            self.database.add(modifyOp)
                         } else {
                             self.container.add(modifyOp)
                         }

From 4cdb79f641810b77aeff672c910903b2fc8b0821 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Fri, 8 Apr 2022 16:16:21 +0800
Subject: [PATCH 20/25] Support pause sync object

---
 IceCream/Classes/SyncEngine.swift | 34 ++++++++++++++++-----------
 IceCream/Classes/SyncObject.swift | 38 ++++++++++++++++++++++++-------
 IceCream/Classes/Syncable.swift   |  2 ++
 3 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index 4e1ebf59..e851b729 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -89,22 +89,30 @@ extension SyncEngine {
         databaseManager.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordsIDsToDelete, completion: completionHandler)
     }
 
-    public func startObservingLocalAndRemoteChanges() {
-        stopObservingLocalAndRemoteChanges() // Avoid add observer for multiple times.
+//    public func startObservingLocalAndRemoteChanges() {
+//        stopObservingLocalAndRemoteChanges() // Avoid add observer for multiple times.
+//
+//        if self.databaseManager is PrivateDatabaseManager {
+//            databaseManager.registerLocalDatabase()
+//        }
+//        databaseManager.startObservingRemoteChanges()
+//        databaseManager.startObservingTermination()
+//    }
+//
+//    public func stopObservingLocalAndRemoteChanges() {
+//        if self.databaseManager is PrivateDatabaseManager {
+//            databaseManager.unregisterLocalDatabase()
+//        }
+//        databaseManager.stopObservingRemoteChanges()
+//        databaseManager.stopObservingTermination()
+//    }
 
-        if self.databaseManager is PrivateDatabaseManager {
-            databaseManager.registerLocalDatabase()
-        }
-        databaseManager.startObservingRemoteChanges()
-        databaseManager.startObservingTermination()
+    public func partiallyPauseSync() {
+        databaseManager.syncObjects.forEach { $0.pause() }
     }
 
-    public func stopObservingLocalAndRemoteChanges() {
-        if self.databaseManager is PrivateDatabaseManager {
-            databaseManager.unregisterLocalDatabase()
-        }
-        databaseManager.stopObservingRemoteChanges()
-        databaseManager.stopObservingTermination()
+    public func resumeSync() {
+        databaseManager.syncObjects.forEach { $0.resume() }
     }
 }
 
diff --git a/IceCream/Classes/SyncObject.swift b/IceCream/Classes/SyncObject.swift
index 1fe31a13..7c17c082 100644
--- a/IceCream/Classes/SyncObject.swift
+++ b/IceCream/Classes/SyncObject.swift
@@ -28,15 +28,21 @@ public final class SyncObject<T, U, V, W> where T: Object & CKRecordConvertible
     private let pendingUTypeRelationshipsWorker = PendingRelationshipsWorker<U>()
     private let pendingVTypeRelationshipsWorker = PendingRelationshipsWorker<V>()
     private let pendingWTypeRelationshipsWorker = PendingRelationshipsWorker<W>()
-    
+
+    public var canPauseSync: Bool
+    private var isPaused: Bool
+
     public init(
         realmConfiguration: Realm.Configuration = .defaultConfiguration,
         type: T.Type,
+        canPauseSync: Bool = true,
         uListElementType: U.Type? = nil,
         vListElementType: V.Type? = nil,
         wListElementType: W.Type? = nil
     ) {
         self.realmConfiguration = realmConfiguration
+        self.canPauseSync = canPauseSync
+        self.isPaused = false
     }
     
 }
@@ -127,14 +133,30 @@ extension SyncObject: Syncable {
             }
         }
     }
-    
+
+    public func pause() {
+        guard self.canPauseSync else {
+            return
+        }
+
+        self.isPaused = true
+    }
+
+    public func resume() {
+        guard self.canPauseSync else {
+            return
+        }
+
+        self.isPaused = false
+    }
+
     /// When you commit a write transaction to a Realm, all other instances of that Realm will be notified, and be updated automatically.
     /// For more: https://realm.io/docs/swift/latest/#writes
     public func registerLocalDatabase() {
         BackgroundWorker.shared.start {
             let realm = try! Realm(configuration: self.realmConfiguration)
             self.notificationToken = realm.objects(T.self).observe({ [weak self](changes) in
-                guard let self = self else { return }
+                guard let self = self, !self.isPaused else { return }
                 switch changes {
                 case .initial(_):
                     break
@@ -151,11 +173,11 @@ extension SyncObject: Syncable {
         }
     }
 
-    public func unregisterLocalDatabase() {
-        BackgroundWorker.shared.start {
-            self.notificationToken = nil
-        }
-    }
+//    public func unregisterLocalDatabase() {
+//        BackgroundWorker.shared.start {
+//            self.notificationToken = nil
+//        }
+//    }
     
     public func resolvePendingRelationships() {
         pendingUTypeRelationshipsWorker.resolvePendingListElements()
diff --git a/IceCream/Classes/Syncable.swift b/IceCream/Classes/Syncable.swift
index b1457c18..818a54e6 100644
--- a/IceCream/Classes/Syncable.swift
+++ b/IceCream/Classes/Syncable.swift
@@ -32,6 +32,8 @@ public protocol Syncable: class {
     
     /// CloudKit related
     func pushLocalObjectsToCloudKit()
+    func pause()
+    func resume()
     
     /// Callback
     var pipeToEngine: ((_ recordsToStore: [CKRecord], _ recordIDsToDelete: [CKRecord.ID]) -> ())? { get set }

From 80ffa3eab1722d220265536848581b8792042182 Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Fri, 8 Apr 2022 16:22:57 +0800
Subject: [PATCH 21/25] =?UTF-8?q?=E6=B3=A8=E9=87=8A=E6=8E=89=20unregisterL?=
 =?UTF-8?q?ocalDatabase=20=E6=96=B9=E6=B3=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/DatabaseManagerProtocol.swift |  2 +-
 IceCream/Classes/PrivateDatabaseManager.swift  | 14 +++++++-------
 IceCream/Classes/PublicDatabaseManager.swift   | 14 +++++++-------
 IceCream/Classes/Syncable.swift                |  2 +-
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 0d1cd43c..e55dfd81 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -39,7 +39,7 @@ protocol DatabaseManager: class {
     func stopObservingTermination()
     func createDatabaseSubscriptionIfHaveNot()
     func registerLocalDatabase()
-    func unregisterLocalDatabase()
+//    func unregisterLocalDatabase()
     
     func cleanUp()
 }
diff --git a/IceCream/Classes/PrivateDatabaseManager.swift b/IceCream/Classes/PrivateDatabaseManager.swift
index 14c0d155..74092969 100644
--- a/IceCream/Classes/PrivateDatabaseManager.swift
+++ b/IceCream/Classes/PrivateDatabaseManager.swift
@@ -155,13 +155,13 @@ final class PrivateDatabaseManager: DatabaseManager {
         }
     }
 
-    func unregisterLocalDatabase() {
-        self.syncObjects.forEach { object in
-            DispatchQueue.main.async {
-                object.unregisterLocalDatabase()
-            }
-        }
-    }
+//    func unregisterLocalDatabase() {
+//        self.syncObjects.forEach { object in
+//            DispatchQueue.main.async {
+//                object.unregisterLocalDatabase()
+//            }
+//        }
+//    }
     
     private func fetchChangesInZones(_ callback: ((Error?) -> Void)? = nil) {
         let changesOp = CKFetchRecordZoneChangesOperation(recordZoneIDs: zoneIds, optionsByRecordZoneID: zoneIdOptions)
diff --git a/IceCream/Classes/PublicDatabaseManager.swift b/IceCream/Classes/PublicDatabaseManager.swift
index 171337bc..6719a05c 100644
--- a/IceCream/Classes/PublicDatabaseManager.swift
+++ b/IceCream/Classes/PublicDatabaseManager.swift
@@ -75,13 +75,13 @@ final class PublicDatabaseManager: DatabaseManager {
         }
     }
 
-    func unregisterLocalDatabase() {
-        self.syncObjects.forEach { object in
-            DispatchQueue.main.async {
-                object.unregisterLocalDatabase()
-            }
-        }
-    }
+//    func unregisterLocalDatabase() {
+//        self.syncObjects.forEach { object in
+//            DispatchQueue.main.async {
+//                object.unregisterLocalDatabase()
+//            }
+//        }
+//    }
     
     // MARK: - Private Methods
     private func excuteQueryOperation(queryOperation: CKQueryOperation,on syncObject: Syncable, callback: ((Error?) -> Void)? = nil) {
diff --git a/IceCream/Classes/Syncable.swift b/IceCream/Classes/Syncable.swift
index 818a54e6..69bd26ec 100644
--- a/IceCream/Classes/Syncable.swift
+++ b/IceCream/Classes/Syncable.swift
@@ -23,7 +23,7 @@ public protocol Syncable: class {
     
     /// Realm Database related
     func registerLocalDatabase()
-    func unregisterLocalDatabase()
+//    func unregisterLocalDatabase()
     func cleanUp()
     func add(record: CKRecord)
     func delete(recordID: CKRecord.ID)

From 10f783309587c6b8792670a48c0bc44161ec5cce Mon Sep 17 00:00:00 2001
From: Alen Liang <simplyaalen@gmail.com>
Date: Fri, 8 Apr 2022 16:34:50 +0800
Subject: [PATCH 22/25] =?UTF-8?q?=E6=81=A2=E5=A4=8D=E6=B3=A8=E9=87=8A?=
 =?UTF-8?q?=E7=9A=84=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Classes/DatabaseManagerProtocol.swift     |  2 +-
 IceCream/Classes/PrivateDatabaseManager.swift | 14 ++++----
 IceCream/Classes/PublicDatabaseManager.swift  | 14 ++++----
 IceCream/Classes/SyncEngine.swift             | 34 +++++++++----------
 IceCream/Classes/SyncObject.swift             | 10 +++---
 IceCream/Classes/Syncable.swift               |  2 +-
 6 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index e55dfd81..0d1cd43c 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -39,7 +39,7 @@ protocol DatabaseManager: class {
     func stopObservingTermination()
     func createDatabaseSubscriptionIfHaveNot()
     func registerLocalDatabase()
-//    func unregisterLocalDatabase()
+    func unregisterLocalDatabase()
     
     func cleanUp()
 }
diff --git a/IceCream/Classes/PrivateDatabaseManager.swift b/IceCream/Classes/PrivateDatabaseManager.swift
index 74092969..14c0d155 100644
--- a/IceCream/Classes/PrivateDatabaseManager.swift
+++ b/IceCream/Classes/PrivateDatabaseManager.swift
@@ -155,13 +155,13 @@ final class PrivateDatabaseManager: DatabaseManager {
         }
     }
 
-//    func unregisterLocalDatabase() {
-//        self.syncObjects.forEach { object in
-//            DispatchQueue.main.async {
-//                object.unregisterLocalDatabase()
-//            }
-//        }
-//    }
+    func unregisterLocalDatabase() {
+        self.syncObjects.forEach { object in
+            DispatchQueue.main.async {
+                object.unregisterLocalDatabase()
+            }
+        }
+    }
     
     private func fetchChangesInZones(_ callback: ((Error?) -> Void)? = nil) {
         let changesOp = CKFetchRecordZoneChangesOperation(recordZoneIDs: zoneIds, optionsByRecordZoneID: zoneIdOptions)
diff --git a/IceCream/Classes/PublicDatabaseManager.swift b/IceCream/Classes/PublicDatabaseManager.swift
index 6719a05c..171337bc 100644
--- a/IceCream/Classes/PublicDatabaseManager.swift
+++ b/IceCream/Classes/PublicDatabaseManager.swift
@@ -75,13 +75,13 @@ final class PublicDatabaseManager: DatabaseManager {
         }
     }
 
-//    func unregisterLocalDatabase() {
-//        self.syncObjects.forEach { object in
-//            DispatchQueue.main.async {
-//                object.unregisterLocalDatabase()
-//            }
-//        }
-//    }
+    func unregisterLocalDatabase() {
+        self.syncObjects.forEach { object in
+            DispatchQueue.main.async {
+                object.unregisterLocalDatabase()
+            }
+        }
+    }
     
     // MARK: - Private Methods
     private func excuteQueryOperation(queryOperation: CKQueryOperation,on syncObject: Syncable, callback: ((Error?) -> Void)? = nil) {
diff --git a/IceCream/Classes/SyncEngine.swift b/IceCream/Classes/SyncEngine.swift
index e851b729..ab88331e 100644
--- a/IceCream/Classes/SyncEngine.swift
+++ b/IceCream/Classes/SyncEngine.swift
@@ -89,23 +89,23 @@ extension SyncEngine {
         databaseManager.syncRecordsToCloudKit(recordsToStore: recordsToStore, recordIDsToDelete: recordsIDsToDelete, completion: completionHandler)
     }
 
-//    public func startObservingLocalAndRemoteChanges() {
-//        stopObservingLocalAndRemoteChanges() // Avoid add observer for multiple times.
-//
-//        if self.databaseManager is PrivateDatabaseManager {
-//            databaseManager.registerLocalDatabase()
-//        }
-//        databaseManager.startObservingRemoteChanges()
-//        databaseManager.startObservingTermination()
-//    }
-//
-//    public func stopObservingLocalAndRemoteChanges() {
-//        if self.databaseManager is PrivateDatabaseManager {
-//            databaseManager.unregisterLocalDatabase()
-//        }
-//        databaseManager.stopObservingRemoteChanges()
-//        databaseManager.stopObservingTermination()
-//    }
+    public func startObservingLocalAndRemoteChanges() {
+        stopObservingLocalAndRemoteChanges() // Avoid add observer for multiple times.
+
+        if self.databaseManager is PrivateDatabaseManager {
+            databaseManager.registerLocalDatabase()
+        }
+        databaseManager.startObservingRemoteChanges()
+        databaseManager.startObservingTermination()
+    }
+
+    public func stopObservingLocalAndRemoteChanges() {
+        if self.databaseManager is PrivateDatabaseManager {
+            databaseManager.unregisterLocalDatabase()
+        }
+        databaseManager.stopObservingRemoteChanges()
+        databaseManager.stopObservingTermination()
+    }
 
     public func partiallyPauseSync() {
         databaseManager.syncObjects.forEach { $0.pause() }
diff --git a/IceCream/Classes/SyncObject.swift b/IceCream/Classes/SyncObject.swift
index 7c17c082..784c2ca9 100644
--- a/IceCream/Classes/SyncObject.swift
+++ b/IceCream/Classes/SyncObject.swift
@@ -173,11 +173,11 @@ extension SyncObject: Syncable {
         }
     }
 
-//    public func unregisterLocalDatabase() {
-//        BackgroundWorker.shared.start {
-//            self.notificationToken = nil
-//        }
-//    }
+    public func unregisterLocalDatabase() {
+        BackgroundWorker.shared.start {
+            self.notificationToken = nil
+        }
+    }
     
     public func resolvePendingRelationships() {
         pendingUTypeRelationshipsWorker.resolvePendingListElements()
diff --git a/IceCream/Classes/Syncable.swift b/IceCream/Classes/Syncable.swift
index 69bd26ec..818a54e6 100644
--- a/IceCream/Classes/Syncable.swift
+++ b/IceCream/Classes/Syncable.swift
@@ -23,7 +23,7 @@ public protocol Syncable: class {
     
     /// Realm Database related
     func registerLocalDatabase()
-//    func unregisterLocalDatabase()
+    func unregisterLocalDatabase()
     func cleanUp()
     func add(record: CKRecord)
     func delete(recordID: CKRecord.ID)

From 8939fc966f4bb9138ebd536b5585921a61d08334 Mon Sep 17 00:00:00 2001
From: Liu Yi <61upup@gmail.com>
Date: Thu, 28 Apr 2022 15:21:03 +0800
Subject: [PATCH 23/25] Cancel fetched long-lived operation if it is not
 finished

---
 IceCream/Classes/DatabaseManagerProtocol.swift | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/IceCream/Classes/DatabaseManagerProtocol.swift b/IceCream/Classes/DatabaseManagerProtocol.swift
index 0d1cd43c..f53674dd 100644
--- a/IceCream/Classes/DatabaseManagerProtocol.swift
+++ b/IceCream/Classes/DatabaseManagerProtocol.swift
@@ -62,11 +62,23 @@ extension DatabaseManager {
                 self.container.fetchLongLivedOperation(withID: id, completionHandler: { [weak self](ope, error) in
                     guard let self = self, error == nil else { return }
                     if let modifyOp = ope as? CKModifyRecordsOperation {
-                        modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
-                            print("🍦 Resume modify records success!")
+                        if #available(iOS 15, *) {
+                            modifyOp.modifyRecordsResultBlock = { result in
+                                print("🍦 modify result: \(result)")
+                            }
+                        } else {
+                            modifyOp.modifyRecordsCompletionBlock = { (_,_,_) in
+                                print("🍦 Resume modify records success!")
+                            }
                         }
+                        
+                        if let isFinished = ope?.isFinished, !isFinished {
+                            print("🍦 Cancel operation")
+                            ope?.cancel()
+                        }
+
                         if #available(iOS 15, *) {
-                            print("🍦 Add operation: fetchLongLivedOperation")
+                            print("🍦 Add fetched long-lived operation")
                             self.database.add(modifyOp)
                         } else {
                             self.container.add(modifyOp)

From 72c26f878cc9240fd4c3b4f04b24f7551fc26ab4 Mon Sep 17 00:00:00 2001
From: Liu Yi <61upup@gmail.com>
Date: Sat, 30 Apr 2022 11:05:10 +0800
Subject: [PATCH 24/25] =?UTF-8?q?=E4=B8=B4=E6=97=B6=E6=9B=B4=E6=96=B0=20lo?=
 =?UTF-8?q?g=20=E6=96=B9=E5=BC=8F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 IceCream/Classes/Manifest.swift | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/IceCream/Classes/Manifest.swift b/IceCream/Classes/Manifest.swift
index 4d00644d..d9fb9022 100644
--- a/IceCream/Classes/Manifest.swift
+++ b/IceCream/Classes/Manifest.swift
@@ -17,19 +17,15 @@ public class IceCream {
     /// If you don't want to see them in your console, just set `enableLogging` property to false.
     /// The default value is true.
     public var enableLogging: Bool = true
-    
+    public var print: ((Any...) -> Void)? = nil
 }
 
 /// If you want to know more,
 /// this post would help: https://medium.com/@maxcampolo/swift-conditional-logging-compiler-flags-54692dc86c5f
 internal func print(_ items: Any..., separator: String = " ", terminator: String = "\n") {
     if (IceCream.shared.enableLogging) {
-        #if DEBUG
-        var i = items.startIndex
-        repeat {
-            Swift.print(items[i], separator: separator, terminator: i == (items.endIndex - 1) ? terminator : separator)
-            i += 1
-        } while i < items.endIndex
-        #endif
+        if let print = IceCream.shared.print {
+            print(items)
+        }
     }
 }

From 045af2aae256d3109da4ec4d8f3253aa9cde8107 Mon Sep 17 00:00:00 2001
From: Liu Yi <61upup@gmail.com>
Date: Mon, 2 May 2022 18:48:30 +0800
Subject: [PATCH 25/25] =?UTF-8?q?Revert=20"=E4=B8=B4=E6=97=B6=E6=9B=B4?=
 =?UTF-8?q?=E6=96=B0=20log=20=E6=96=B9=E5=BC=8F"?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This reverts commit 72c26f878cc9240fd4c3b4f04b24f7551fc26ab4.
---
 IceCream/Classes/Manifest.swift | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/IceCream/Classes/Manifest.swift b/IceCream/Classes/Manifest.swift
index d9fb9022..4d00644d 100644
--- a/IceCream/Classes/Manifest.swift
+++ b/IceCream/Classes/Manifest.swift
@@ -17,15 +17,19 @@ public class IceCream {
     /// If you don't want to see them in your console, just set `enableLogging` property to false.
     /// The default value is true.
     public var enableLogging: Bool = true
-    public var print: ((Any...) -> Void)? = nil
+    
 }
 
 /// If you want to know more,
 /// this post would help: https://medium.com/@maxcampolo/swift-conditional-logging-compiler-flags-54692dc86c5f
 internal func print(_ items: Any..., separator: String = " ", terminator: String = "\n") {
     if (IceCream.shared.enableLogging) {
-        if let print = IceCream.shared.print {
-            print(items)
-        }
+        #if DEBUG
+        var i = items.startIndex
+        repeat {
+            Swift.print(items[i], separator: separator, terminator: i == (items.endIndex - 1) ? terminator : separator)
+            i += 1
+        } while i < items.endIndex
+        #endif
     }
 }