You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/aws-sdk-rust/sdk/aws-smithy-types/src/date_time
    
    the code of the file until where you have to start completion: /*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

//! DateTime type for representing Smithy timestamps.

use crate::date_time::format::rfc3339::AllowOffsets;
use crate::date_time::format::DateTimeParseErrorKind;
use num_integer::div_mod_floor;
use num_integer::Integer;
use std::cmp::Ordering;
use std::convert::TryFrom;
use std::
    
    fn from(time: SystemTime) -> Self {
        if time < UNIX_EPOCH {
            let duration = UNIX_EPOCH.duration_since(time).expect("time < UNIX_EPOCH");
            let mut secs = -(duration.as_secs() as i128);
            let mut nanos = duration.subsec_nanos() as i128;
            if nanos != 0 {
                secs -= 1;
                nanos = NANOS_PER_SECOND - nanos;
            }
            DateTime::from_nanos(secs * NANOS_PER_SECOND + nanos)
                .expect("SystemTime has same precision as DateTime")
        } else {
            let duration = time.duration_since(UNIX_EPOCH).expect("UNIX_EPOCH <= time");
            DateTime::from_secs_and_nanos(
                i64::try_from(duration.as_secs())
                    .expect("SystemTime has same precision as DateTime"),
                duration.subsec_nanos(),
            )
        }
    }