Implement Content Image

```swift
var contents: Any?
An object that provides the contents of the layer. Animatable.

var contentsRect: CGRect
The rectangle, in the unit coordinate space, that defines the portion of the layer’s contents that should be used. Animatable.

var contentsCenter: CGRect
The rectangle that defines how the layer contents are scaled if the layer’s contents are resized. Animatable.

func display()
Reloads the content of this layer.

func draw(in: CGContext)
Draws the layer’s content using the specified graphics context.
```