Add a bit of documentation to describe the problem this is solving

AsyncDisplayKit/ASCollectionView.mm

@@ -645,6 +645,9 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
     if (_ignoreMaxSizeChange) {
       _ignoreMaxSizeChange = NO;
     } else {
+      // This actually doesn't perform an animation, but prevents the transaction block from being processed in the
+      // data controller's prevent animation block that would interupt an interupted relayout happening in an animation block
+      // ie. ASCollectionView bounds change on rotation or mutl-tasking split view resize.
       [self performBatchAnimated:YES updates:^{
         [_dataController relayoutAllNodes];
       } completion:nil];