[DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)][return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetDiskFreeSpaceEx(
string lpDirectoryName,
out ulong lpFreeBytesAvailableToCaller,
out ulong lpTotalNumberOfBytes,
out ulong lpTotalNumberOfFreeBytes
);