The performance screen is useful, but all of the assets are showing with high load times. Most of the asynchronous calls happening on our site is in the background and typically does not affect the user. I believe there should be a setting that allows exclusion of the "Children" portion from the load times and site performance score.
Working with our site performance team, the numbers from Raygun do not match up to the ones we've tested through other platforms and tools. Taking the "Children" portion out, it's a much closer number. Asynchronous assets are asynchronous, so it shouldn't affect the end user unless it's waiting on data to be loaded for display. Our sites are statically generated with lightweight APIs handling some of the dynamic data, the rest of the time is due to tag managers, analytics platforms and various other third-party tools we have on the site.