disconnect method

@override Future<ByteChannel?> disconnect()

Implementation

@override
Future<ByteChannel?> disconnect() async {
  C? sock = _sock;
  bool ok = sock == null || await doDisconnect(sock);
  if (!ok) {
    assert(false, 'failed to disconnect socket: $sock');
    return null;
  }
  // remoteAddress = null;
  return sock is ByteChannel ? sock as ByteChannel : null;
}