[WIP] Add add support for Timestamp type by frsyuki · Pull Request #431 · msgpack/msgpack-java

@mattbishop We haven't decided how to add above two things; whether to add MessageFormat
type and ValueType for describing timestamp.

In the msgpack spec, timestamp is just one of the Extention types. We think adding these two additional types will be convenient for timestamp users. However, adding these types is a big change to the API (since most of the users is using switch case statement for checking data type, so rewriting will be necessary by adding case Timestamp: ...). We need to be careful so as not to break user programs that started to use timestamp types in future versions.