title: How to call a function half way through the scroll controller in flutter
body: <p>I have a GridView that loads lazily at the end of the scroll controller, however I want to load the data when I reach halfway through the scroll controller. If I try to do an if statement that checks if the scroll has reached 50% of the controller it will never become equal, however, if I do a greater than equal to 50% it calls the function multiple times ending in duplicates of data. How can I avoid this duplication or is there a better way to do this.</p>