feat(iOS): scroll edge appearance

[dylancom]

This let's you define the edge appearance of the tabbar.
Allowing for a tabbar that is transparent when there is no content behind the tabbar.

@okwasniewski I am a bit in doubt what we should initially set this to... It seems that if you have a tabbarcontroller it modifies this to transparent by default? Do we want it transparent by default (on the scroll edge) or not... hmm...

If the value of this property is nil, UIKit uses the value of the tab bar’s standardAppearance property, modified to have a transparent background. If no tab bar controller manages your tab bar, UIKit ignores this property and uses the tab bar’s standard appearance.

[okwasniewski]

Hmm I don't really see the difference between opaque and transparent. Can we make it a booean? something like: transparentScrollEdgeApperance?

I think setting (configureWithDefaultBackground()) as default makes sense

[dylancom]

Haven't tested opaque clearly but thought it was neat to expose all available options as it was a small effort.

[okwasniewski]

Haven't tested opaque clearly but thought it was neat to expose all available options as it was a small effort.

On the one hand it's neat but on the other it introduces confusion for users. If we have two options that do almost the same then let's make it easier.

Probably we need to annotate that transparentScrollEdgeApperance shouldn't be used together with lazy loading as this causes background blinking.

[dylancom]

Is the lazy loading at all needed with this library (perf wise)? As in using it as default...

[okwasniewski]

Is the lazy loading at all needed with this library (perf wise)? As in using it as default...

It is, if someone renders a huge list in one of the tabs then it can cause issues. Also lazy is the default on JS Tabs so we are matching the "standard".

Maybe Im missing why there is transparent and opaque so let's expose it as you mentioned.

I would set default as our default and make transparent / opaque opt-in

[dylancom]

Yes, default is currently our default :)

[okwasniewski]

Thanks for working on this! Two last docs changes