@available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
extension Measurement : Codable {
    private enum CodingKeys : Int, CodingKey {
        case value
        case unit
    }

    private enum UnitCodingKeys : Int, CodingKey {
        case symbol
        case converter
    }

    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        let value = try container.decode(Double.self, forKey: .value)

        let unitContainer = try container.nestedContainer(keyedBy: UnitCodingKeys.self, forKey: .unit)
        let symbol = try unitContainer.decode(String.self, forKey: .symbol)

        let unit: UnitType
        if UnitType.self is Dimension.Type {
            let converterData = try unitContainer.decode(Data.self, forKey: .converter)
            let converter = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(converterData) as? UnitConverter
            let unitMetaType = (UnitType.self as! Dimension.Type)
            if let converter = converter {
                unit = (unitMetaType.init(symbol: symbol, converter: converter) as! UnitType)
            } else {
                unit = UnitType(symbol: symbol)
            }
        } else {
            unit = UnitType(symbol: symbol)
        }

        self.init(value: value, unit: unit)
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(self.value, forKey: .value)

        var unitContainer = container.nestedContainer(keyedBy: UnitCodingKeys.self, forKey: .unit)
        try unitContainer.encode(self.unit.symbol, forKey: .symbol)

        if UnitType.self is Dimension.Type {
            let converter = (self.unit as! Dimension).converter
            let converterData = try NSKeyedArchiver.archivedData(withRootObject: converter, requiringSecureCoding: false)
            try unitContainer.encode(converterData, forKey: .converter)
        }
    }
}