init(for factory: AnyFactory, with contextTasks: [AnyContextTask] = [], transformer: AnyContextTransformer? = nil) {

        self.factory = factory

        self.contextTasks = contextTasks

        self.transformer = transformer

    }

    mutating func add(_ contextTask: AnyContextTask) {

        contextTasks.append(contextTask)

    }

    mutating func prepare(with context: AnyContext) throws {

        let context = transformer.flatMap { InPlaceTransformingAnyContext(context: context, transformer: $0) } ?? context

        try factory.prepare(with: context)

        contextTasks = try contextTasks.map {

            var contextTask = $0

            try contextTask.prepare(with: context)

            return contextTask

        }

    }

    func build(with context: AnyContext, in childViewControllers: inout [UIViewController]) throws {

        let context = transformer.flatMap { InPlaceTransformingAnyContext(context: context, transformer: $0) } ?? context

        let viewController = try factory.build(with: context)

        try contextTasks.forEach { try $0.perform(on: viewController, with: context) }

        try factory.action.perform(embedding: viewController, in: &childViewControllers)

    }

    public var description: String {

        String(describing: factory)

    }