I have an example of the question. I am interested in at least making sure all the elements in my header load promptly. For instance, on Mobile View on my Google Pixel, in the latest version of Chrome on the latest version of Android, on my site the Search plugin and the Cart icon take a significant amount of time to load, while every other element on the page will be first loaded. There is no signalling of loading elements in the header, so it just looks like a blank space until the elements finally appear. On Mobile view I want the Header to load first! First impressions lead to repeat experiences.
Thank you.