Global pre-request functions with pm.sendRequest do not wait for callback execution


I define the following collection-level pre-request script to be re-used by my collection’s requests:

utils = {
    testAsync : function() {
            {url : ''}, // URL set to Google for testing
            (error, response) => {

However, when calling utils.testAsync() in a pre-request script of any of my collection’s requests Postman does not wait for the callback to be executed before proceeding to the actual request. What would I need to modify to fix this?

The way of making code globally accessible is based on this answer on the forum.

Thank you