#6 Updated documentation

Author: malcommac

README.md

@@ -613,7 +613,15 @@ class ViewController: ScrollStackController, ScrollStackControllerDelegate {
   func scrollStackRowDidBecomeHidden(_ stackView: ScrollStack, row: ScrollStackRow, index: Int, state: ScrollStack.RowVisibility) {
     // Row did become partially or entirely invisible.
   }
-	
+
+  func scrollStackDidUpdateLayout(_ stackView: ScrollStack) {
+    // This function is called when layout is updated (added, removed, hide or show one or more rows).
+  }
+
+  func scrollStackContentSizeDidChange(_ stackView: ScrollStack, from oldValue: CGSize, to newValue: CGSize) {
+    // This function is called when content size of the stack did change (remove/add, hide/show rows).
+  }
+
 }
 ```