Add crate for integration with the AWS SDK for Rust

[snaggen]

I have implemented some basic conversion from the AWS Smithy type DateTime into/from Timestamp and Zoned.

[robertbastian]

Wouldn't this be better in aws_smithy_types_convert like the chrono and time conversions?

[snaggen]

I created a PR for that previously, but they didn't want to add it since jiff isn't stable yet.

[BurntSushi]

Ref smithy-lang/smithy-rs#3826

I'll get to reviewing this soon, after I get through the batch of changes related to core-only work.

[snaggen]

Ref smithy-lang/smithy-rs#3826

I'll get to reviewing this soon, after I get through the batch of changes related to core-only work.

No, worries.... it is just some simple convenience helpers, so it is not like my code is dependent on this :)

[fiadliel]

The nanosecond portion of a jiff Timestamp are negative for times before the Unix epoch (it ranges between +1s and -1s), this should be taken into account (e.g. the type casts between u32 and i32 are incorrect).

[snaggen]

The nanosecond portion of a jiff Timestamp are negative for times before the Unix epoch (it ranges between +1s and -1s), this should be taken into account (e.g. the type casts between u32 and i32 are incorrect).

The smithy datetime is defined as seconds and nano seconds since unix epoch, so a simple check for that should fix this. I will have a look at it later.

[snaggen]

@fiadliel Ok, it seems that I was wrong about DateTime being only positive. But I have added nano second conversions for times before epoc. Please have a look and see if it looks correct to you. I checked for conversion the other way also, but that seems to be handled by jiff automatically.