function wrapProp(prop, xhr) {
	            if (prop in xhr && isFunction(xhr[prop])) {
	                fill(xhr, prop, function (orig) {
	                    return self.wrap(orig);
	                }); // intentionally don't track filled methods on XHR instances
	            }
	        }
Instrument browser built-ins w/ breadcrumb capturing
 - XMLHttpRequests
 - DOM interactions (click/typing)
 - window.location changes
 - console

Can be disabled or individually configured via the `autoBreadcrumbs` config option