bug: passing scrollRef causes element being pinned to top without respecting height of nodes before the scrollview

[hirbod]

Assume the following structure:

<TrueSheet>
  <MyHeaderComponent />
  <FlashList />
</TrueSheet>

All good so far. But once I pass the scrollRef (with FlashList, unlike FlatList, you need to pass the scrollableNode like so):

ref={(ref) => {
  if (scrollRef) {
    ;(scrollRef.current as unknown) = ref?.getScrollableNode()
  }
}}

It works fine. The main problem I have is that (at least on iOS; I haven't tested Android yet), there is a utility function called pinTo, which now pins the whole view behind MyHeaderComponent, thus not taking the element's height into account.

I've experimented with TrueSheetView and tested adding offsets like so:

rctScrollView.pinTo(view: contentView) { constraints in
    constraints.top?.constant = 50 // 50 is the height of my header
}

So this works. I think there are multiple ways to solve this problem:

1. Add a HeaderComponent, similar to FooterComponent, and handle all of this under the hood.
2. Ensure to run through all the siblings of TrueSheet before the actual ScrollView and automatically calculate the offset.
3. Add a prop (like scrollViewOffset), and we pass a value to it, like 50

Before Patch	After Patch

You may ask why I don't use HeaderComponent by FlashList? Well, because it does not keep the header fixed.

My example above is just a quick "test", not a fix. The offset needs to be reflected in all calculations etc, similar to the footer.