Override WordPress wp_mail function

Question

I know there is a filter for wp_mail, but I don't want to only change arguments. I'm trying to reimplement wp_mail with a custom RESTful API, so I need to change the functionality of wp_mail. How can I do that?! Thanks.

Answer 1

Just declare your function again in theme's functions.php.

function wp_mail(){
    echo 'TEST';
}