func timestamp(_ timeZoneHour: Int = 0,
               _ year: Int? = nil,
               _ month: Int? = nil,
               _ day: Int? = nil,
               _ hour: Int? = nil,
               _ minute: Int? = nil,
               _ second: Int? = nil,
               _ fraction: Double? = nil ) -> Date {
    let calendar = Calendar(identifier: .gregorian)
    let timeZone = TimeZone(secondsFromGMT: timeZoneHour * 60 * 60)
    let nanosecond = fraction.map { Int($0 * Double(NSEC_PER_SEC)) }
    let datecomponents = DateComponents(calendar: calendar, timeZone: timeZone,
                          year: year, month: month, day: day,
                          hour: hour, minute: minute, second: second, nanosecond: nanosecond)
    // Using `DateComponents.date` causes crash on Linux
    guard let date = NSCalendar(identifier: .gregorian)?.date(from: datecomponents) else {
        fatalError("Never happen this")
    }
    return date
}