In my project, I'm using Octocrab to talk to the GitHub API. Octocrab uses Chrono for representing times, whereas my project is using Time internally. This led to me having to convert between them a bunch, and I ended up writing a small crate to do that.
So here it is, version 0.2.0 of Timetraveler, which does exactly that (0.1.0 pointed to the wrong repository). I might add conversions for more crates (or std::time) in the future - but I honestly only know of Time and Chrono, so I stuck with those right now.
Usage is pretty simple: you get extension traits for converting to a representation and then an implementation for the respective representation in the other crate.
use timetraveler::{chrono::AsDateTime, time::AsOffsetDateTime};
use time::{macros::datetime, OffsetDateTime};
use chrono::{DateTime, Utc, FixedOffset};
use chrono_tz::{Tz, Europe::Stockholm};
use rxpect::{expect, expectations::EqualityExpectations};
// A time::OffsetDateTime
let dt = datetime!(2024-01-01 12:00:00 +02:00);
// Convert to chrono::DateTime<Utc>
let utc: DateTime<Utc> = dt.as_date_time_utc();
expect(utc.to_rfc3339().as_ref()).to_equal("2024-01-01T10:00:00+00:00");
// Convert to chrono::DateTime<FixedOffset>
let offset: DateTime<FixedOffset> = dt.as_date_time_offset();
expect(offset.to_rfc3339().as_ref()).to_equal("2024-01-01T12:00:00+02:00");
// Convert to chrono::DateTime<Stockholm>
let stockholm: DateTime<Tz> = dt.as_date_time(Stockholm);
expect(stockholm.to_rfc3339().as_ref()).to_equal("2024-01-01T11:00:00+01:00");
// Convert back to time::OffsetDateTime
let roundtrip: OffsetDateTime = stockholm.as_offset_date_time();
expect(roundtrip).to_equal(dt);
There's a post on my blog with some more details—or mostly more words, the above example is pretty much everything you need 