Thread: render a view then another ?????

in my controller I have a call to a remote API that is a little slow to answer.
it takes 2-3 seconds for the answer to come so I would like to display a "please wait page is loading" animated gif in a div,.

my problem is that the view is not rendered till the end of the controller when the api call is done so I would like to load a "loading.phtml" at the beginning of the controler and then load a final index.phtml at the end of the controller once all is loaded.

any help is welcome