fix unsigned to signed conversion bug

[GregoryLakewood]

Casting u32 into i32 and then extending into i64 does not hold the value when val_u32 > i32::MAX.
As explained in Microsoft Documentation one should firstly construct u64 from FILETIME and then perform arithmetics.

[jhpratt]

LGTM. As this won't affect (non-artificial) timestamps for 14 years, I won't be cutting a release specifically for this.

[GregoryLakewood]

Thank you.
@jhpratt Could you look into this? I found this bug because I am getting Err(IndeterminateOffset) on my machine.
That breaks some Rust tools I use, specifically probe-rs.
From my understanding 31bit in lower FILETIME DWORD toggles every 2^31*100 nanoseconds what equals roughly 3 and half minutes.

[jhpratt]

Ha, I wasn't thinking of the fact that it represents 100 nanosecond intervals. I was only off by a factor of ten million.

I'll be having another release later today.

[jhpratt]

Released.