ParentDataScope
Scope for reading typed parent data from one direct child.
Access is valid only during the callback lifetime of the extending measure or layout scope and only on the owning tree thread. A component scope starts at the requested direct child's outermost modifier and scans its consecutive modifier chain through the innermost modifier, stopping before that component node. A modifier scope starts at its requested effective child and scans only the consecutive inner modifier chain, also stopping before the logical component node. The innermost matching referential key wins. The component node and all entries below it are never queried.