let s1 = Board.Page("Step1", "Lorem ipsum", "img_in_xcassets")
let s2 = Board.Page("Step2", "Lorem ipsum", "home_avatar")
let s3 = Board.Page("Step3", "Lorem ipsum", "http://meniny.cn/assets/images/default.jpg")

let alertView = Board(pages: [s1, s2, s3])
alertView.delegate = self // BoardDelegate
alertView.show()

class SomeClass: BoardDelegate {
    func board(_ b: Board, didTriggerAction action: Board.Action, step: Int, total: Int) {
        switch action {
        case .skipped:
            print("Board: skipped the \(step) step")
        case .completed:
            print("Board: completed!")
        default:
            print("Board: Go to next step! \(step)")
        }
    }
}