code: public void close() throws IOException {
          if (isClosed()) {
              return;
          }
  
          if (!_webSocket.isDisconnected()) {
              String s = "Can't close the MessageReader if the WebSocket is " +
                         "still connected";
              throw new WebSocketException(s);
          }
          
          _sharedQueue.done();
          _closed = true;
      }
docs: not part of the public API.