Option to cache loaded flag

[sunarya-thito]

Currently, the widget will always request the flag image from assets directly on widget build. This is not optimal if you put the widget inside ListView where widgets constantly being disposed and rebuilt on user scroll. The widget should cache loaded image and use the cached image where possible to avoid frequent asset loading. This is a very serious problem for flutter web apps where asset loading will create a fetch request directly, and with this widget, it can cause accidental request spam.

[arturograu]

Hi @sunarya-thito ! That would be a significant improvement for the package. Unfortunately, I don't have the time to work on these kind of enhancements right now. If I find time in the future I can explore the issue you are mentioning. However, please feel free to submit a PR.