public void connect(IOCallback callback) {
		if (setAndConnect(null, callback) == false) {
			if (callback == null)
				throw new RuntimeException("callback may not be null.");
			else if (this.url == null)
				throw new RuntimeException(
						"connect(IOCallback) can only be invoked after SocketIO(String) or SocketIO(URL)");
		}
	}
connects to an already set host. Do only use this method if you
instantiate {@link SocketIO} using {@link #SocketIO(String)} or
{@link #SocketIO(URL)}.

@param callback
           the callback
src/io/socket/SocketIO.java