To have a better separation of concern between messages and how they are conveyed in connectors.
BECMessage can be simple dataclasses, leaving the serialization to the connector which transport those.
The serialization module itself can be isolated, and in the case of msgpack it can be extended to
understand how to encode/decode BECMessage, to simplify writing code like with BundleMessage or to
be able to automatically encode numpy or BECStatus objects.
Finally, client objects (producers and consumers) can receive BECMessage objects instead of having
to dump or load themselves.
