Changelog and some comments

CHANGELOG.md

@@ -22,6 +22,9 @@ The changelog for `MessageKit`. Also see the [releases](https://github.com/Messa
 - Added `additionalBottomInset` property that allows to adjust the bottom content inset automatically set on the messages collection view by the view controller. 
 [#787](https://github.com/MessageKit/MessageKit/pull/787) by [@andreyvit](https://github.com/andreyvit)
 
+- Added new methods to simplify using of custom messages: `customCellSizeCalculator(for:at:in:)` for `MessagesLayoutDelegate` and `customCell(for:at:in:)` for `MessagesDataSource`.
+[#879](https://github.com/MessageKit/MessageKit/pull/879) by [@realbonus](https://github.com/RealBonus)
+
 ### Fixed
 
 - Fixed bottom content inset adjustment when using an undocked keyboard on iPad, or when `edgesForExtendedLayout` does not include `.top`, or when a parent container view controller adds extra views at the top of the screen. 

Sources/Controllers/MessagesViewController.swift

@@ -180,6 +180,8 @@ UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
         return collectionView.messagesDataSource?.numberOfItems(inSection: section, in: collectionView) ?? 0
     }
 
+    /// Note:
+    ///   If you override this method, remember to call MessagesDataSource's customCell(for:at:in:) for MessageKind.custom messages, if necessary
     open func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
 
         guard let messagesCollectionView = collectionView as? MessagesCollectionView else {

Sources/Layout/MessagesCollectionViewFlowLayout.swift

@@ -135,6 +135,8 @@ open class MessagesCollectionViewFlowLayout: UICollectionViewFlowLayout {
     lazy open var videoMessageSizeCalculator = MediaMessageSizeCalculator(layout: self)
     lazy open var locationMessageSizeCalculator = LocationMessageSizeCalculator(layout: self)
 
+    /// - Note:
+    ///   If you override this method, remember to call MessageLayoutDelegate's customCellSizeCalculator(for:at:in:) method for MessageKind.custom messages, if necessary
     open func cellSizeCalculatorForItem(at indexPath: IndexPath) -> CellSizeCalculator {
         let message = messagesDataSource.messageForItem(at: indexPath, in: messagesCollectionView)
         switch message.kind {