A dependency-free, sans-I/O SCTP implementation for WebRTC Data Channels (RFC 9260, 8831, 8260, 6525, 3758, 9653) in modern Java. A 1:1 port of the WebRTC team's dcSCTP Rust implementation: the socket performs no I/O and spawns no threads; the caller feeds it received packets, advances a virtual clock, and drains generated events.