PHP: Output data before and after sleep()?

[StupidShouldHurt]

This is purely for learning more about output buffering and nothing more. What I wish to do is echo a string to the browser, sleep 10 seconds, and then echo something else. Normally the browser would wait the full 10 seconds and then post the whole result, how I would I stop that? An example:\[code\]ob_start();echo "one";sleep(10);echo "two";\[/code\]