How to initialize all tabs

I have tabs with 4 pages. When App starts, how do I initialize or run the constructors of all 4 tabs (pages) without navigating (opening the pages). I need all of these 4 main pages constructors to run at startup and I can’t figure out how to do that. Damn lazy loading…

Why? This seems like a weird requirement to me. Pages shouldn’t care how and when they are loaded.