title: How do you set the duration for UICollectionView Animations?
body: <p>I have a custom flow layout which is adjusting the attributes for cells when they are being inserted and deleted from the CollectionView with the following two functions, but I'm unable to figure out how you would adjust the default animation duration.</p>
  
  <pre><code>- (UICollectionViewLayoutAttributes *)initialLayoutAttributesForAppearingItemAtIndexPath:(NSIndexPath *)itemIndexPath {
      UICollectionViewLayoutAttributes* attributes = [self layoutAttributesForItemAtIndexPath:itemIndexPath];
  
      // Assign the new layout attributes
      attributes.transform3D = CATransform3DMakeScale(0.5, 0.5, 0.5);
      attributes.alpha = 0;
  
      return attributes;
  }
  
  - (UICollectionViewLayoutAttributes *)finalLayoutAttributesForDisappearingItemAtIndexPath:(NSIndexPath *)itemIndexPath {
  
      UICollectionViewLayoutAttributes* attributes = [self layoutAttributesForItemAtIndexPath:itemIndexPath];
  
      // Assign the new layout attributes
      attributes.transform3D = CATransform3DMakeScale(0.5, 0.5, 0.5);
      attributes.alpha = 0;
  
      return attributes;
  }
  </code></pre>