SelectionListNode
data class SelectionListNode<ID : Any>(val id: ID, val title: String, val subtitle: String? = null, val leadingGlyph: String? = null, val children: List<SelectionListNode<ID>> = emptyList())
A node in a one- or two-level SelectionList tree.
A node without children is a leaf that is selected when tapped. A node with children is an expandable parent: tapping it shows its children inline, and selecting one reports that child's id. Identifiers must be unique across the whole tree; they are list keys and the values the list reports.