Optional ReadonlyhostThe interface to bind. Omitted binds every interface, which is what a LAN surface wants;
'127.0.0.1' is how a test or a locked-down deployment keeps it to the machine.
ReadonlyportThe port to bind. Always supplied by the caller — there is no registered port for any protocol this carries, and a compiled-in default would borrow another product's meaning.
Optional ReadonlysocketSocket factory (override for tests). Defaults to real dgram.
Configuration for UdpEndpoint.