CrystalCompatible

public protocol CrystalCompatible : AnyObject

A type that has crystal extensions. You can use cst property to get extension methods.

// Make `UIView` conform to `CrystalCompatible`.
extension UIView: CrystalCompatible {
    public typealias Theme: AppTheme
}

When conforming to CrystalCompatible, you have to determine the concrete theme type in the conformance.