Anywise

- new, `MessageRegistry.register` method
provides a flexible and versatile way to register handlers in an imperative manner.

py
user_registry.register(
LogginGuard,
handler_create,
handler_update,
pre_hanldes=[validate_command, add_start_time],
post_handles=[validate_result],
)

register union types

- refactory MessageRegistry
- add a source support

- pre-defined `Event` class
- docs
- global guard

- add dependency injection to guard
- scoped send