lazy var の遅延参照？という面白い動き ref: http://qiita.com/lovee/items/5f68762cb46c70af0c9a

file0.swift

struct Data {

    var int = 1

    mutating func increase(completion: (Int) -> Void) {
        self.int += 1
        completion(self.int)
    }

}

class Manager {

    var data = Data()

    var int: Int {
        return self.data.int
    }

    func increase() {
        self.data.increase { (i) in
            print(i)
            print(self.int)
        }
    }

}

let manager = Manager()
manager.increase()