preferredFormat property
The preferred format to encode and decode the date. If DateTimeFormat.auto is used, the format will be determined based on the decoder / encoder. If DateTimeFormat.iso8601 is used, the date will be encoded as an ISO8601 string. If DateTimeFormat.unixMilliseconds is used, the date will be encoded as a unix milliseconds integer.
If the format supports custom de/encoding of DateTime, this is ignored.
Implementation
final DateTimeFormat preferredFormat;