Depending on the goals of the page I would say its not up to the developer either. Developer/designer/pm whoever should ask the user: is this part of the page/c

Depending on the goals of the page I would say its not up to the developer either. Developer/designer/pm whoever should ask the user: is this part of the page/content meaningful to you to load first? Unless you have something specific you want to communicate and then its up to you to decide whatever you find meaningful to show first.