Priority tasks for rendering, signal based deferral, event scheduler

Hi all!

This entry is more like a question than a classical post.
Time-to-time, when I attend or watch a presentation about a big frontend project, the presenter mentions some event scheduling, signal based deferral or splitting rendering based on priority tasks and render parts of the UI only if the higher priority parts are already rendered. But to be honest, I was not able to find any detailed resource how and what is the best way to integrate this on a Vue / React / Polymer / Angular / whatever based UI.
Is there any existing lib for this? Is there any blog post / training / video about how to integrate it?