The offset (in points) at which to place the callout bubble.
- iOS 3.0+
- macOS 10.9+
- tvOS 9.2+
This property determines the additional distance by which to move the callout bubble. When this property is set to (0, 0), the anchor point of the callout bubble is placed on the top-center point of the annotation view’s frame. Specifying positive offset values moves the callout bubble down and to the right, while specifying negative values moves it up and to the left.