OffsetDateTime type supports the following patterns:
G: General invariant ISO-8601 pattern, down to the second. This corresponds to the custom pattern
uuuu'-'MM'-'dd'T'HH':'mm':'sso<G>. This is the default format pattern.
o: Extended invariant ISO-8601 pattern, down to the nanosecond. This will round-trip values except for the calendar system. This corresponds to the custom pattern
r: Full round-trip pattern including calendar system. This corresponds to the custom pattern
The custom format patterns for the local date and time parts of the value are the same as the custom patterns for
LocalDateTime. There is an additional specifier for the offset.
The "o" specifier must always be followed by a pattern for
Offset within angle brackets. The pattern may be a standard pattern or a custom pattern. For example, a pattern of
uuuu-MM-dd HH:mm:ss o<G> might produce output of "2013-07-17 06:20:35 Z" or "2013-07-17 07:20:35 +01".
To use culture-specific standard date or time patterns in a custom
OffsetDateTime pattern, use some combination of the following specifiers:
LocalDatepattern within angle brackets
LocalTimepattern within angle brackets
LocalDateTimepattern within angle brackets
For example, to use a culture-specific short date format, but a fixed time format,
followed by the offset in general form, you might use a pattern of
ld<d> HH:mm:ss o<G>