close method
Closes like a peer close, then waits for the handler side to reap.
Implementation
Future<void> close([int code = 1000]) async {
_native._wsMessages.add(
RawWsMessage(
payload: Uint8List(0),
connectionId: _id,
kind: 8,
aux: code,
),
);
await closedCode.timeout(const Duration(seconds: 5));
}