Expose the cache

[GrimDev]

Hi there,

Thanks for the lib, it works very well.

But, I have an issue : I need to display images as SVGs in some cases, for that I use react-native-svg that works well but enforces to use their Image component that does'nt support cache purposes.

This component needs an href prop to link the image, it would be really nice if we could have an exposed function from FastImage that might call its cache.