# Architecture
The crate is centered on three types:
- `PublicationConfig`: immutable configuration for one multicast destination
- `Publication`: one ready-to-send non-blocking UDP socket
- `Context`: a lightweight owner for multiple publications
Design choices:
- publications are connected UDP sockets, so repeated sends do not rebuild the
destination address on the hot path
- sockets are non-blocking by default, which keeps them easy to integrate into
event loops and async adapters
- IPv4 and IPv6 socket setup stay in separate implementation branches
- the resolved destination is stored on the `Publication`, which matters for
IPv6 scope-ID handling
- the default feature set stays small; metrics, Tokio, and raw packet support
are opt-in
- `raw-packets` owns multicast forwarding semantics, while `raw-ip` is a
separate caller-built IP datagram transport primitive for control traffic