sectionKeys method
Section keys in render order. Excludes pending-deletion sections
unless includeExiting is true.
Implementation
List<K> sectionKeys({bool includeExiting = false}) {
_checkNotDisposed();
final keys = includeExiting ? _tree.rootKeys : _tree.liveRootKeys;
return <K>[
for (final k in keys)
if (_assertIsSection(k)) (k as SectionKey<K>).value,
];
}