SwaggerUI bundle - Cancel request for Spec on page load

Hi, I need to cancel the initial request for the swaggerspec in SwaggerUI Bundle. I need the user to enter their credentials first and then hit the Explore button.
I have tried assigning a requestInterceptor. In here I am able to do things like Adding headers etc, but am not able to cancel the request
e.g
requestInterceptor: function (req) {
if (req.loadSpec && req.method != "OPTIONS") {
if (!($('#input_username').val() === undefined)) {

                        var hash = btoa($('#input_username').val() + ":" + $('#input_password').val()); 
                        headers['Authorization'] = "Basic " + hash;
                        req.loadSpec = true;
                       
                    }
                    else {
                        alert('Setting loadspec to false');
                        req.loadSpec = false;
                        //Cancel the request here!!!???
                        
                    }
                }

Start by tracing SwaggerUI Bundle's initial spec-loading request and how requestInterceptor handles requests, using the behavior described in the issue as the entry point. Done means the initial spec request waits until the user enters credentials and selects Explore, while subsequent requests continue to work normally.