Updated example and v2 of lazy_load_scrollview

[stargazing-dino]

Hello ! I didn't know of the existence of this package and ended up creating listview notifier similar to this but slightly different. In any case, I'd like to offer it up as a PR. To improve I took both my ideas and your ideas and kind of squashed them together as well as implemented a few things from the issues here.

Here are a few things the new:

• lazyloadscrollview takes an optional ScrollController now that will work in place of bubbling notifier events (this is useful to avoid predicates)
• Added notificationPredicate #15
• Added an example on how to add animation when reached the end #2
• lazyloadscrollview can now work in both directions of a listview
• Added debounce timer that will prevent the callback from firiing a bunch of times

Breaking change:

• the lazyloadscrollview takes a builder instead of a child. This builder passes through isLoadingBefore and isLoadingAfter that tell the user when the respective async op is running.
• Renamed onEndOfPage to to onLoadAfter

I'd love to get your opinion on this big change. Leaving it as a draft for now

[QuirijnGB]

Hey Thanks for this and sorry for the late response. Ill have a look this week!

[QuirijnGB]

I have not forgotten about this! Ill get to it soon