broker-message

A message sent to or received from a broker.

The body is a stream<u8>: the payload flows incrementally on both the producing and the consuming side, so neither end is required to hold it whole in memory. Hosts whose backend cannot stream a message (e.g. core NATS, which sends a message as one bounded payload) MAY buffer a body internally before forwarding it — the interface permits streaming without requiring every backend to provide it, and a backend that can fan a stream out efficiently pays no buffering cost.