Swfit获取系统开机时间BootTime

开机时间获取，注意重置系统闹钟会重置

extension UIDevice {
    var bootTime: TimeInterval? {
        var tv = timeval()
        var tvSize = MemoryLayout<timeval>.size
        let err = sysctlbyname("kern.boottime", &tv, &tvSize, nil, 0);
        guard err == 0, tvSize == MemoryLayout<timeval>.size else {
            return nil
        }
        return Double(tv.tv_sec) + Double(tv.tv_usec) / 1_000_000.0
    }
}

// 使用
UIDevice.current.bootTime