How do you optimize the performance of a custom widget with a large number of children?

To optimize the performance of a custom widget with a large number of children, employing the 'ListView.builder' constructor is a common strategy. This constructor efficiently creates children on-demand, only rendering those that are currently visible on the screen. This approach reduces the memory footprint and improves the overall performance by avoiding the creation and rendering of all children at once. It is a key optimization technique when dealing with a dynamic or extensive list of items in Flutter.