Extremely slow to load json

[JCKodel]

I was using https://pub.dev/packages/lottie to render Lottie animations, but it doesn't render animations very well (for instance: xvrh/lottie-flutter#323).

So, I used this library, which renders that animation correctly, but, it is extremely slow to load a json (generated by https://pub.dev/packages/dart_animated_emoji).

It is so slow that navigation animation freezes completely (almost 1 second of stuttering while changing the json or navigating to a page where the viewer is on).