function stateChange() {
                if (this.readyState == 4) {
                    this.onreadystatechange = empty;
                    self.posting = false;

                    if (this.status == 200) {
                        self.socket.setBuffer(false);
                    } else {
                        self.onClose();
                    }
                }
            }
Posts a encoded message to the Socket.IO server.

@param {String} data A encoded message.
@api private