Breaking changes
- Direct message constants (`KILL_MSG`, `PAUSE_MSG`, `PLAY_MSG`, `STATUS_MSG`) are replaced with the `MessageBuilder` class methods.
Features
- Message builder for constructing message with carrying more information (291) [[f760b4a]](https://github.com/aiidateam/plumpy/commit/f760b4aaf6a46bbfc13bab88e36271aab122a641)
- Make Message interface is hidden inside function call (301) [[a4b896]](https://github.com/aiidateam/plumpy/commit/a4b896255a4d92cef7ff3494e915acabd64d97c1)
Devops
- Make rpc callback exception more explicit and wind up to show more infos (305) [[ecef9b9]](https://github.com/aiidateam/plumpy/commit/ecef9b9a4ebbeafacd3b6a84952ad770972f2814)