CABasicAnimation with `keyPath` value set to `fromValue`

CABasicAnimationFromValue.swift

// MARK: - CABasicAnimation
extension CABasicAnimation {
    
    /// Creates a new animation object with its `keyPath` property set to `path` and current `keyPath` value set to `fromValue`.
    convenience init(keyPath path: String, layer: CALayer) {
        self.init(keyPath: path)
        self.fromValue = layer.presentation()?.value(forKeyPath: path)
    }
    
}