I know that it depends on how much you disentangle your network code from your business logic. The question is the degree. Is it enough, or does it just dull the pain?

If you give your business logic the complete message or send it a stream, then the flow of ownership stays much cleaner. And the unit tests stay substantially easier to write and more importantly, to maintain.

I know too many devs who don't see when they bias their decisions to avoid making changes that will lead to conflict with bad unit tests and declare that our testing strategy is Just Fine. It's easier to show than to debate, but it still takes an open mind to accept the demonstration.