Function parse_range 

pub(crate) fn parse_range(
    start: &str,
    end: &str,
) -> Result<(DateTime<Utc>, DateTime<Utc>)>

Parses an RFC 3339 start/end range into UTC instants.

Does not check the order of the two instants; callers do that.

Arguments

• start - Range start, RFC 3339 with any offset.
• end - Range end, RFC 3339 with any offset.

Errors

Returns an error naming start or end if either is not valid RFC 3339.