review: NextBatchContext lock 코드 제거 및 주석 보강

README.md

@@ -210,15 +210,17 @@ Here's how to set up pagination:
       )
     ```
 
-4. Once you’ve finished fetching your data, it is very important to let KarrotListKit know that you have finished the process. To do that, you need to call `completeBatchFetching()` method of `NextBatchContext`. This assures that the whole batch fetching mechanism stays in sync and the next batch fetching cycle can happen.
+4. Once you’ve finished fetching your data, it is very important to let KarrotListKit know that you have finished the process. To do that, you need to call `completeBatchFetching()` method of `NextBatchContext` on Main-Thread(for avoid data race.). This assures that the whole batch fetching mechanism stays in sync and the next batch fetching cycle can happen.
     ```swift
     List(sections: [])
       .onNextBatchTrigger(
         decisionProvider: decisionProvider,
         handler: { event in
           let nextBatchContext = event.context
           fetchNextPage() {
-            nextBatchContext.completeBatchFetching()
+            DispatchQueue.main.async {
+              nextBatchContext.completeBatchFetching()
+            }
           }
         }
       )

Sources/KarrotListKit/List.swift

@@ -70,7 +70,9 @@ extension List {
   ///   handler: { [weak self] context in
   ///     self?.context = context
   ///     self?.fetchNextPage {
-  ///       self?.context.completeBatchFetching()
+  ///       DispatchQueue.main.async {
+  ///         self?.context.completeBatchFetching()
+  ///       }
   ///     }
   ///   }
   ///)

Sources/KarrotListKit/NextBatchTrigger/NextBatchContext.swift

@@ -18,18 +18,15 @@ public class NextBatchContext {
   /// The current state of the batch fetching process.
   private(set) var state: State = .completed
 
-  /// A lock to ensure thread safety when updating the state.
-  private let lock = NSLock()
-
   /// Begins the batch fetching process by setting the state to `fetching`.
   func beginBatchFetching() {
-    lock.lock(); defer { self.lock.unlock() }
     state = .fetching
   }
 
   /// Completes the batch fetching process by setting the state to `completed`.
+  ///
+  /// - Important: Call this function on **Main Thread** for avoid data race.
   public func completeBatchFetching() {
-    lock.lock(); defer { self.lock.unlock() }
     state = .completed
   }
 }