日常bug小记

• 获取手机剩余可用容量不准
  原因：从iOS11.0开始，ytes->KB->MB->G的进制为1000.0，而不是1024.0
  代码：

  let fileUrl = URL(fileURLWithPath: NSTemporaryDirectory())
  let results = try? fileUrl.resourceValues(forKeys:  [URLResourceKey.volumeAvailableCapacityForImportantUsageKey])
       if let availableSize = results?.volumeAvailableCapacityForImportantUsage {
           // ytes->KB->MB->G
           let _availableSize = Double(availableSize) / 1000.0 / 1000.0 / 1000.0
           self.label.text = "已占用\(byte.fileSizeToString())，剩余\(String(format: "%.1f", _availableSize))G可用"
       }