[My last reply must have gone to the ether…]
I’ve encountered whole messages and partial messages. Partial messages have come ordered and unordered; one byte at a time or larger chunks, and I’ve seen bitfields across byte boundaries. I’ve never taken a communication domain model to production. (Leon Starr once told me he was working on one, but I never heard if it got finished.)
Field extraction and recombining was done through bridges.