Flutter › Flutter Slivers & Custom Scroll Effects

How can you properly implement infinite scrolling or pagination within a sliver based scroll view, automatically loading additional new content as a user actively scrolls further down toward the very bottom of the currently loaded list?

Intermediate

Answer

Implementing infinite scrolling within a sliver based scroll view typically involves properly listening to the ScrollController's own current scroll position, actively checking whenever that current position genuinely gets sufficiently close to the very bottom edge of the currently already loaded content, and then automatically triggering a request to load and properly append an entirely new additional page of further content onto your existing underlying data list, then correctly and automatically updating your SliverList so it now properly displays this newly appended additional content seamlessly as part of that exact same single continuous ongoing scroll.
scrollController.addListener(() {
  if (scrollController.position.pixels >= scrollController.position.maxScrollExtent - 200) {
    loadNextPage();
  }
});
Real-world example A social media feed automatically loads and seamlessly appends the next page of additional posts once a user has scrolled to within roughly two hundred pixels of the very bottom of their currently already loaded feed content, creating a genuinely smooth, seamless infinite scrolling experience.

Common follow-ups: How do you properly display a loading indicator specifically while the next additional page is actively still being fetched?;What happens if a user actively scrolls extremely fast, potentially triggering several separate load requests all together nearly simultaneously?