struct Counter<V> : CustomDebugStringConvertible {
    private var _value: V
    private(set) var valueReadCount = 0
    private(set) var valueWriteCount = 0

    init(value: V) {
        self._value = value
    }

    mutating func reset() {
        valueReadCount = 0
        valueWriteCount = 0
    }

    var debugDescription: String {
        return ("\(_value) is read \(valueReadCount) times and written \(valueWriteCount) times")
    }

    var val : V {
        mutating get {
            valueReadCount += 1
            return _value
        }
        set {
            valueWriteCount += 1
            _value = newValue
        }
    }
}