added mechanism to track transaction sources

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/Modern.ColorsDemo.MainView.swift

@@ -102,6 +102,7 @@ extension Modern.ColorsDemo {
 
                     try transaction.deleteAll(From<Modern.ColorsDemo.Palette>())
                 },
+                sourceIdentifier: TransactionSource.clear,
                 completion: { _ in }
             )
         }
@@ -113,6 +114,7 @@ extension Modern.ColorsDemo {
 
                     _ = transaction.create(Into<Modern.ColorsDemo.Palette>())
                 },
+                sourceIdentifier: TransactionSource.add,
                 completion: { _ in }
             )
         }
@@ -127,6 +129,7 @@ extension Modern.ColorsDemo {
                         palette.setRandomHue()
                     }
                 },
+                sourceIdentifier: TransactionSource.shuffle,
                 completion: { _ in }
             )
         }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/Modern.ColorsDemo.swift

@@ -69,5 +69,16 @@ extension Modern {
                 )
             }
         }
+        
+        
+        // MARK: - TransactionSource
+        
+        enum TransactionSource {
+            
+            case add
+            case delete
+            case shuffle
+            case clear
+        }
     }
 }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.UIKit.DetailViewController.swift

@@ -91,7 +91,8 @@ extension Modern.ColorsDemo.UIKit {
         func objectMonitor(
             _ monitor: ObjectMonitor<Modern.ColorsDemo.Palette>,
             didUpdateObject object: Modern.ColorsDemo.Palette,
-            changedPersistentKeys: Set<KeyPathString>
+            changedPersistentKeys: Set<KeyPathString>,
+            sourceIdentifier: Any?
         ) {
             
             self.reloadPaletteInfo(object, changedKeys: changedPersistentKeys)

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.UIKit.ListViewController.swift

@@ -32,17 +32,25 @@ extension Modern.ColorsDemo.UIKit {
         )
         
         /**
-         ⭐️ Sample 2: Once the views are created, we can start binding `ListPublisher` updates to the `DiffableDataSource`. We typically call this at the end of `viewDidLoad`. Note that the `addObserver`'s closure argument will only be called on the succeeding updates, so to immediately display the current values, we need to call `dataSource.apply()` once.
+         ⭐️ Sample 2: Once the views are created, we can start binding `ListPublisher` updates to the `DiffableDataSource`. We typically call this at the end of `viewDidLoad`. Note that the `addObserver`'s closure argument will only be called on the succeeding updates, so to immediately display the current values, we need to call `dataSource.apply()` once. This example inspects the optional `transactionSource` to determine the source of the update which is helpful for debugging or for fine-tuning animations.
          */
         private func startObservingList() {
             
             let dataSource = self.dataSource
-            self.listPublisher.addObserver(self) { (listPublisher) in
+            self.listPublisher.addObserver(self, notifyInitial: true) { (listPublisher, transactionSource) in
                 
-                dataSource.apply(listPublisher.snapshot, animatingDifferences: true)
+                switch transactionSource as? Modern.ColorsDemo.TransactionSource {
+                    
+                case .add,
+                     .delete,
+                     .shuffle,
+                     .clear:
+                    dataSource.apply(listPublisher.snapshot, animatingDifferences: true)
+                    
+                case nil:
+                    dataSource.apply(listPublisher.snapshot, animatingDifferences: false)
+                }
             }
-            
-            dataSource.apply(self.listPublisher.snapshot, animatingDifferences: false)
         }
         
         /**
@@ -74,6 +82,7 @@ extension Modern.ColorsDemo.UIKit {
 
                             transaction.delete(objectIDs: [itemID])
                         },
+                        sourceIdentifier: Modern.ColorsDemo.TransactionSource.delete,
                         completion: { _ in }
                     )