Add a UIRefreshControl to be the indicator of load more function.

Sources/Controllers/MessagesViewController.swift

@@ -34,6 +34,10 @@ open class MessagesViewController: UIViewController {
     /// The `MessageInputBar` used as the `inputAccessoryView` in the view controller.
     open var messageInputBar = MessageInputBar()
     
+    open var messageLoadMoreControl: UIRefreshControl {
+        return messagesCollectionView.messageLoadMoreControl
+    }
+    
     /// A Boolean value that determines whether the `MessagesCollectionView` scrolls to the
     /// bottom on the view's first layout.
     ///

Sources/Views/MessagesCollectionView.swift

@@ -35,6 +35,8 @@ open class MessagesCollectionView: UICollectionView {
     open weak var messagesLayoutDelegate: MessagesLayoutDelegate?
 
     open weak var messageCellDelegate: MessageCellDelegate?
+    
+    open var messageLoadMoreControl = UIRefreshControl()
 
     open var showsDateHeaderAfterTimeInterval: TimeInterval = 3600
 
@@ -51,6 +53,7 @@ open class MessagesCollectionView: UICollectionView {
     public override init(frame: CGRect, collectionViewLayout layout: UICollectionViewLayout) {
         super.init(frame: frame, collectionViewLayout: layout)
         backgroundColor = .white
+        addSubview(messageLoadMoreControl)
     }
     
     required public init?(coder aDecoder: NSCoder) {