Assumption set hinting

Strategies to reload lists vary widely depending on the assumption set. For example:

• If elements all have the same size: when reloading the list, we know exactly how many elements to load to reach the same position as previously.
• If elements never switch order and never change size: we can cache their respective size to compute how many need to be reloaded (how Twitter works).

Instead of trying to find a global solution, maybe we should ask the user to pass a hint to the runtime?

LazyColumn(hint = AllElementsHaveTheSameSize) {
    …
}