WebSocketChannel close code throws exception

[dukefirehawk]

For version 3.0.0, when calling close with a status argument, it throws an exception. Only status.normalClosure which is 1000 works. The rest of the status code seems like not being mapped into the 3000-4999 range which can cause the exception to be thrown.

Code snippet

    var channel = IOWebSocketChannel.connect(...);
    ...
    channel.sink.close(status.goingAway);

Exception

  Invalid argument(s): Invalid argument: 1001, close code must be 1000 or in the range 3000-4999
  package:web_socket/src/utils.dart 10:5                             checkCloseCode
  package:web_socket/src/io_web_socket.dart 108:5                    IOWebSocket.close
  package:web_socket_channel/adapter_web_socket_channel.dart 112:27  new AdapterWebSocketChannel.<fn>.<fn>
  package:stream_channel                                             _GuaranteeSink.close
  package:async/src/delegate/stream_sink.dart 47:27                  DelegatingStreamSink.close
  package:web_socket_channel/adapter_web_socket_channel.dart 147:18  _WebSocketSink.close