Document DateTime format

[arg0d]

C# bindings expect and produce DateTime objects in UTC format. This needs to be documented in some form. #66

[meenzen]

IMHO the generated bindings should be using DateTimeOffset with forced conversion to UTC, like I previously suggested. It is way too easy to make mistakes when using DateTime.

[arg0d]

At this point I don't really remember/understand what's the issue. I'm looking at the chronological test file, and it kinda makes sense. Rust's SystemTime::Now() and DateTime.UtcNow return the same date string. So where is the problem?

[meenzen]

The problem is that it's extremely easy to pass a non-utc DateTime from C#. If the bindings would instead expose DateTimeOffset then this would be impossible. DateTimeOffset is the default for all new APIs. The new TimeProvider class for example only exposes DateTimeOffset.